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64 bit processors

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Anonymous
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a b K Overclocking
December 13, 2004 11:31:43 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

I have a question about the line of true 64 bit processors. When they
are running 32 bit software, do they take the instructions, data,
etc. 2 blocks at a time or is there half of the cpu that is not
being used?? Where this is leading, is to the question is it better
to have a super hi speed 32 bit cpu and OC it, or is it better to
have a 64 bit cpu of less speed. Om that case would they be about
equal? In other words, is it worth it to buy a 64 bit cpu now, even
if it is only running 32 bit software and may still be doing that for
some time??

More about : bit processors

December 14, 2004 2:38:37 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

On Mon, 13 Dec 2004 20:31:43 -0600, Jmonahan@ev1.net wrote:

>I have a question about the line of true 64 bit processors. When they
>are running 32 bit software, do they take the instructions, data,
>etc. 2 blocks at a time or is there half of the cpu that is not
>being used?? Where this is leading, is to the question is it better
>to have a super hi speed 32 bit cpu and OC it, or is it better to
>have a 64 bit cpu of less speed. Om that case would they be about
>equal? In other words, is it worth it to buy a 64 bit cpu now, even
>if it is only running 32 bit software and may still be doing that for
>some time??


The AMD64 chips can run 32-bit just like any other 32-bit x86 CPU,
64-bit is just (free) icing on the cake.

http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=224...
http://reviews.zdnet.co.uk/hardware/0,39023760,39164010...
http://techreport.com/reviews/2004q4/athlon64-fx55/inde...
http://www6.tomshardware.com/cpu/20041115/pentium4_570-...

Ed
Anonymous
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a b K Overclocking
December 14, 2004 2:52:45 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

On Mon, 13 Dec 2004 20:31:43 -0600, Jmonahan wrote:

> I have a question about the line of true 64 bit processors. When they
> are running 32 bit software, do they take the instructions, data,
> etc. 2 blocks at a time or is there half of the cpu that is not
> being used?? Where this is leading, is to the question is it better
> to have a super hi speed 32 bit cpu and OC it, or is it better to
> have a 64 bit cpu of less speed. Om that case would they be about
> equal? In other words, is it worth it to buy a 64 bit cpu now, even
> if it is only running 32 bit software and may still be doing that for
> some time??

64 bits refers to the address size not to data sizes, a 32 bit CPU can
address 4 billion bytes, a 64 bit CPU can address 4 billion X 4 billion
bytes, i.e. 2^64 or 1.6 * 10^18 bytes. We've reached the point where
4GBytes of real memory is not only possible but is even affordable so the
4Gbyte limit of a 32 bit address is a problem. By increasing the address
space to 64 bits the virtual address space becomes so large that the we
won't have to worry about it limiting the amount of RAM that you can put
into a system for another 50 years, probably much much longer than 50
years but if you make the wildly optimistic prediction that Moores law
continues to hold forever then at the rate of 1.5 years per bit (the
historical Moore rate) then it will take 48 years to use up the new
address bits.
Related resources
Anonymous
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a b K Overclocking
December 14, 2004 7:10:38 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

On Mon, 13 Dec 2004 20:31:43 -0600, Jmonahan@ev1.net wrote:

>I have a question about the line of true 64 bit processors. When they
>are running 32 bit software, do they take the instructions, data,
>etc. 2 blocks at a time or is there half of the cpu that is not
>being used?? Where this is leading, is to the question is it better
>to have a super hi speed 32 bit cpu and OC it, or is it better to
>have a 64 bit cpu of less speed. Om that case would they be about
>equal? In other words, is it worth it to buy a 64 bit cpu now, even
>if it is only running 32 bit software and may still be doing that for
>some time??


The answer to the question you didn't ask is, yes buy an
Athlon 64 instead of a P4, at most uses it's faster,
including 32bit.
Anonymous
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a b K Overclocking
December 14, 2004 12:26:40 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

On Mon, 13 Dec 2004 23:52:45 -0500, General Schvantzkoph wrote:

> 64 bits refers to the address size not to data sizes,

Now that's a new one and I thought I'd heard them all.:-) Actually, this
is incorrect too though. The A64 address bus is 40bits, 48 virtual.

> a 32 bit CPU can address 4 billion bytes

Tell me why my 32bit 68000 cpu can only address 16MB then (1 clue, it has
a 24bit address bus). I really haven't checked, but it's very possible to
have a 32bit cpu address more than 4GB. the amount of directly addressable
ram is controlled by the size of the address bus, and has nothing to do
with 32, 64, or 128 bit cpu's.

--
Abit KT7-Raid (KT133) Tbred B core CPU @2400MHz (24x100FSB)
http://mysite.verizon.net/res0exft/cpu.htm
Anonymous
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a b K Overclocking
December 14, 2004 12:26:41 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

On Tue, 14 Dec 2004 09:26:40 +0000, Wes Newell wrote:

> On Mon, 13 Dec 2004 23:52:45 -0500, General Schvantzkoph wrote:
>
>> 64 bits refers to the address size not to data sizes,
>
> Now that's a new one and I thought I'd heard them all.:-) Actually, this
> is incorrect too though. The A64 address bus is 40bits, 48 virtual.
>
>> a 32 bit CPU can address 4 billion bytes
>
> Tell me why my 32bit 68000 cpu can only address 16MB then (1 clue, it has
> a 24bit address bus). I really haven't checked, but it's very possible to
> have a 32bit cpu address more than 4GB. the amount of directly addressable
> ram is controlled by the size of the address bus, and has nothing to do
> with 32, 64, or 128 bit cpu's.

The physical address space of a CPU is almost never identical to the
virtual address. The virtual address space is what the programmer sees, so
in a 32 bit architecture that's 4G and in 64 bit architecture it's
1.6*10^19. The physical address space is determined by the width of the
Address Translation Unit RAM and the address pins on the CPU. The physical
address space is a choice that the CPU designers make for each design.
Pins and RAM cost money so you don't want to support a physical address
space that's larger than the maximum amount of RAM that the particular CPU
is ever likely to have. When the 68000 came out the biggest DRAM was 64K,
the CPU designers would have figured that at the end of life of the chip
the biggest DRAM would be the 1M DRAM so they picked 16M as the physical
address space because it was confortably larger then any real memory
system that it would ever have to support without being excessively
expensive. When you get to the end of an architecture's life, as we are
now with the 32 bit x86 architecture, it becomes possible to have more
real memory then virtual memory. The way this is handled is that CPUs can
support multiple virtual address spaces, each of which can have it's own
DRAM space. So a Xeon might have 16 separate threads each of which can
address 4G of RAM for a total of 64G of real memory. Each thread is still
limited to 4G but you can have lots of them. There are also ways to give
programmers access to more memory by using segmentation registers which
allows the programmers to manage multiple virtual memory spaces within one
process, that's what the 80286 did to extend the 16 bit address space of
the 8086. Segmentation is a horrible way to handle memory, a larger linear
address space is much easier for programmers to deal with. The AMD64
architecture is now back to where we were in the 68K days. The virtual
address space is so large that all the RAMs in the world couldn't fill it.
The programmer sees the 64 bit space but the actual amount of physical RAM
supported is much smaller, I'm not sure what the exact size is but I
suspect it's around 40 bits (1 terabyte) which would be confortably larger
than the amount of RAM that this generation of chips is likely to have to
support (assuming 4G and maybe even 16G RAMs by the time the last current
generation A64s are unplugged).
Anonymous
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a b K Overclocking
December 14, 2004 4:45:07 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

Without getting complicated, you are always using the full CPU capability.
You are not using 1/2 a CPU to do the work. When the 64 bit CPU runs 32 bit
software, it will function as if it was a 32 bit unit.

I would only spend the extra amount if I was having the necessity of a 64
bit CPU. You will need the 64 bit operating system to take advantage of it
from an operating system point of view. If you are not running 64 bit
capable software's there will also not be any advantage. Very few software's
at this time are written in the 64 bit format.

If you are buying this for future investment, this is not a good idea from
the point of view, that next year or whatever, the 64 bit machines may be
different, and some other need will arise, still making your machine
obsolete in it own way.

Buy what you need for now to get your job done the way you require it to be
done. To some extent, you can do upgrades to the existing system as they are
required. When your system becomes too obsolete, in let's say about 3 years
from now, then it would be worth to start over again on a new system with
the same philosophy.

--

Jerry G.
======


<Jmonahan@ev1.net> wrote in message
news:qljsr05mpgh8mk8i3e3rlvs64ad7jghnhp@4ax.com...
I have a question about the line of true 64 bit processors. When they
are running 32 bit software, do they take the instructions, data,
etc. 2 blocks at a time or is there half of the cpu that is not
being used?? Where this is leading, is to the question is it better
to have a super hi speed 32 bit cpu and OC it, or is it better to
have a 64 bit cpu of less speed. Om that case would they be about
equal? In other words, is it worth it to buy a 64 bit cpu now, even
if it is only running 32 bit software and may still be doing that for
some time??
December 14, 2004 4:48:32 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

"Wes Newell" <w.newell@TAKEOUTverizon.net> wrote in message
news:p an.2004.12.14.09.27.26.358422@TAKEOUTverizon.net...
> On Mon, 13 Dec 2004 23:52:45 -0500, General Schvantzkoph wrote:
>
>> 64 bits refers to the address size not to data sizes,
>
> Now that's a new one and I thought I'd heard them all.:-) Actually, this
> is incorrect too though. The A64 address bus is 40bits, 48 virtual.
>
>> a 32 bit CPU can address 4 billion bytes
>
> Tell me why my 32bit 68000 cpu can only address 16MB then (1 clue, it has
> a 24bit address bus). I really haven't checked, but it's very possible to
> have a 32bit cpu address more than 4GB. the amount of directly addressable
> ram is controlled by the size of the address bus, and has nothing to do
> with 32, 64, or 128 bit cpu's.

The view posted by General Whateverhisnameis may be incorrect, but its an
*incredibly* common misconception.

I can't count the number of articles I have read that was lyrical about the
benefits of 64-bit being the increased address space. Presumably the author
having no clue that it would be perfectly possible to have a 16-bit (let
alone 32-bit) processor with a 48-bit or 64-bit address bus.

Chip
Anonymous
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a b K Overclocking
December 14, 2004 4:48:33 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

> > Tell me why my 32bit 68000 cpu can only address 16MB then (1 clue, it
has
> > a 24bit address bus). I really haven't checked, but it's very possible
to
> > have a 32bit cpu address more than 4GB. the amount of directly
addressable
> > ram is controlled by the size of the address bus, and has nothing to do
> > with 32, 64, or 128 bit cpu's.
>
> The view posted by General Whateverhisnameis may be incorrect, but its an
> *incredibly* common misconception.
>
> I can't count the number of articles I have read that was lyrical about
the
> benefits of 64-bit being the increased address space. Presumably the
author
> having no clue that it would be perfectly possible to have a 16-bit (let
> alone 32-bit) processor with a 48-bit or 64-bit address bus.

Here's what's going on: A 32-bit processer really can only address 4
gigabytes of memory in a single address space. There are hacks like PAE
that let you put more than 4 gigs in a machine, but a single process can
only see 4 gigs of memory. That's it, there's no way around it. If you
disagree, don't argue, try getting a single process to allocate more than 4
gigs on the OS of your choice on a 32-bit processer. Come back when you've
done it.

The A64/Opterons, being 64 bit processers, can address up to a 64-bit
memory address, which is unfathomably huge. However, I believe that they
currently have only a 48-bit memory bus, which is still a boat-load of
memory.

However, going from a 32-bit instruction set to a 64-bit instruction set
with all other items equal can (and does) incur a slight overhead, as you
have to pump more bits around to get the same things accomplished. It's
generally along the lines of 1%-3% real-world performance. However, in the
case of the A64/Opteron, all other items are NOT equal - in 64-bit mode, the
new instruction set allows you to utilize a larger number of registers,
which gives you a real-world performance BOOST of around 10% in most apps.

steve
Anonymous
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a b K Overclocking
December 14, 2004 8:18:23 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

Chip wrote:
> "Wes Newell" <w.newell@TAKEOUTverizon.net> wrote in message
>> On Mon, 13 Dec 2004 23:52:45 -0500, General Schvantzkoph wrote:
>>
>>> 64 bits refers to the address size not to data sizes,
>>
>> Now that's a new one and I thought I'd heard them all.:-) Actually,
>> this is incorrect too though. The A64 address bus is 40bits, 48
>> virtual.
>>
>>> a 32 bit CPU can address 4 billion bytes
>>
>> Tell me why my 32bit 68000 cpu can only address 16MB then (1 clue,
>> it has a 24bit address bus). I really haven't checked, but it's
>> very possible to have a 32bit cpu address more than 4GB. the
>> amount of directly addressable ram is controlled by the size of
>> the address bus, and has nothing to do with 32, 64, or 128 bit
>> cpu's.
>
> The view posted by General Whateverhisnameis may be incorrect, but
> its an *incredibly* common misconception.
>
> I can't count the number of articles I have read that was lyrical
> about the benefits of 64-bit being the increased address space.
> Presumably the author having no clue that it would be perfectly
> possible to have a 16-bit (let alone 32-bit) processor with a
> 48-bit or 64-bit address bus.

There are several factors here. First is the address field in the
actual instructions, which are very likely to be (or to become) 64
bits. Second is the address field in the physical i/o interface,
which is likely to be 32 bits, or capable of 4G of physical
memory. Third is the actual memory attached, which I will assume
to be the common 1G. These three quantities must be strictly
decreasing (or same) in the order I have given them.

The operating system will be the only thing actually aware of the
real physical limits. It will arrange to map all 64 bit addresses
(via tables) into one of: a) disk location b) real memory location
c) invalid. The hardware (or even the OS software) will arrange
that any access to b) is intercepted and converted into a), while
any c) is flagged as a gross error and something serious done about
it. At the same time it can map process specific virtual addresses
(in a known address space) into the larger physical address space,
giving the ability to write all programs as if they had a machine
to themselves.

The efficiency of this mapping is crucial to the apparent speed of
the system under load.

--
Chuck F (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home.att.net&gt; USE worldnet address!
Anonymous
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a b K Overclocking
December 14, 2004 10:51:31 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

On Tue, 14 Dec 2004 08:50:44 -0500, General Schvantzkoph wrote:

> On Tue, 14 Dec 2004 09:26:40 +0000, Wes Newell wrote:
>
>> On Mon, 13 Dec 2004 23:52:45 -0500, General Schvantzkoph wrote:
>>
>>> 64 bits refers to the address size not to data sizes,
>>
>> Now that's a new one and I thought I'd heard them all.:-) Actually, this
>> is incorrect too though. The A64 address bus is 40bits, 48 virtual.
>>
>>> a 32 bit CPU can address 4 billion bytes
>>
>> Tell me why my 32bit 68000 cpu can only address 16MB then (1 clue, it has
>> a 24bit address bus). I really haven't checked, but it's very possible to
>> have a 32bit cpu address more than 4GB. the amount of directly addressable
>> ram is controlled by the size of the address bus, and has nothing to do
>> with 32, 64, or 128 bit cpu's.
>
> The physical address space of a CPU is almost never identical to the
> virtual address. The virtual address space is what the programmer sees, so
> in a 32 bit architecture that's 4G and in 64 bit architecture it's
> 1.6*10^19. The physical address space is determined by the width of the
> Address Translation Unit RAM and the address pins on the CPU. The physical
> address space is a choice that the CPU designers make for each design.
> Pins and RAM cost money so you don't want to support a physical address
> space that's larger than the maximum amount of RAM that the particular CPU
> is ever likely to have. When the 68000 came out the biggest DRAM was 64K,
> the CPU designers would have figured that at the end of life of the chip
> the biggest DRAM would be the 1M DRAM so they picked 16M as the physical
> address space because it was confortably larger then any real memory
> system that it would ever have to support without being excessively
> expensive. When you get to the end of an architecture's life, as we are
> now with the 32 bit x86 architecture, it becomes possible to have more
> real memory then virtual memory. The way this is handled is that CPUs can
> support multiple virtual address spaces, each of which can have it's own
> DRAM space. So a Xeon might have 16 separate threads each of which can
> address 4G of RAM for a total of 64G of real memory. Each thread is still
> limited to 4G but you can have lots of them. There are also ways to give
> programmers access to more memory by using segmentation registers which
> allows the programmers to manage multiple virtual memory spaces within one
> process, that's what the 80286 did to extend the 16 bit address space of
> the 8086. Segmentation is a horrible way to handle memory, a larger linear
> address space is much easier for programmers to deal with. The AMD64
> architecture is now back to where we were in the 68K days. The virtual
> address space is so large that all the RAMs in the world couldn't fill it.
> The programmer sees the 64 bit space but the actual amount of physical RAM
> supported is much smaller, I'm not sure what the exact size is but I
> suspect it's around 40 bits (1 terabyte) which would be confortably larger
> than the amount of RAM that this generation of chips is likely to have to
> support (assuming 4G and maybe even 16G RAMs by the time the last current
> generation A64s are unplugged).

Aha, so now they consider the bitness of the cpu to be the maximum
possible address space within the architecture if you're sumize is
correct. I wonder who keeps changing the nomenclature. In the beginning it
was defined by the data bus size, then it changed to register size (I
think Intel was the first to do this, with the 8088). Motorola redefined
thier 16bit 68000 to calling it a 32bit later. And now we have a bitness
that virtually has nothing to do with anything speed wise, actual ram
address size or anything of any value. Next thing you know they'll be
adding up all the bus widths of the cpu and calling it an xxxx bit cpu.
Got to one up the competition.

--
Abit KT7-Raid (KT133) Tbred B core CPU @2400MHz (24x100FSB)
http://mysite.verizon.net/res0exft/cpu.htm
Anonymous
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a b K Overclocking
December 14, 2004 11:56:37 PM

Archived from groups: alt.comp.hardware.overclocking.amd (More info?)

Think of it like this. 32 bit like taking a half gallon container and
filling a larger container,64 bit is taking a 1 gallon container and filling
the same larger container. the 1 gallon container will take less trips. DOUG
Anonymous
a b à CPUs
a b K Overclocking
December 15, 2004 12:17:44 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

> Aha, so now they consider the bitness of the cpu to be the maximum
> possible address space within the architecture if you're sumize is
> correct. I wonder who keeps changing the nomenclature. In the beginning
> it was defined by the data bus size, then it changed to register size (I
> think Intel was the first to do this, with the 8088). Motorola redefined
> thier 16bit 68000 to calling it a 32bit later. And now we have a bitness
> that virtually has nothing to do with anything speed wise, actual ram
> address size or anything of any value. Next thing you know they'll be
> adding up all the bus widths of the cpu and calling it an xxxx bit cpu.
> Got to one up the competition.

It's always been the virtual address space that defined the bitness of a
CPU architecture. I've been in the business for 30 years and I spent the
first half of my career designing CPUs. Some marketing types in the
early days of microprocessors may have used bus size to define the bitness
of a microprocessor but no computer architect ever did that. The problem
with using register width or bus width is that it isn't consistant even
within a single CPU. The floating point registers in a 16 bit minicomputer
were 64 bits wide, that didn't make the computer a 64 bit computer. The
same thing goes for the memory datapath. The 939 pin Athlon 64s have two
64 bit memory buses, does that make them a 128 bit processor? of course
not. By the same token as serial buses like PCI express and SATA replace
parallel buses does that make the machines 1 bit processors? It is true
that the integer registers generally are the same width as the address
because you use the integer registers to compute addresses in most
architectures. However it's not required, you could use a pair of
registers to hold an address pointer. You can also have specialized
registers that are used only for addresses and other registers that are
used for general purpose integer arithmetic. In fact the base x86
architecture does use a god awful collection of single purpose registers
rather than a uniform general purpose register set.
Anonymous
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a b K Overclocking
December 15, 2004 1:48:02 AM

Archived from groups: alt.comp.hardware.overclocking.amd (More info?)

courseyauto@aol.com (Courseyauto) wrote in
news:20041214155637.00362.00001843@mb-m17.aol.com:

> Think of it like this. 32 bit like taking a half gallon
> container and filling a larger container,64 bit is taking a 1 gallon
> container and filling the same larger container. the 1 gallon
> container will take less trips. DOUG

But it's heavier and will tire you out faster. You'll probably end up with
tendonitus, too.
Anonymous
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a b K Overclocking
December 15, 2004 2:36:44 AM

Archived from groups: alt.comp.hardware.overclocking.amd (More info?)

courseyauto@aol.com (Courseyauto) wrote in
news:20041214155637.00362.00001843@mb-m17.aol.com:

> Think of it like this. 32 bit like taking a half gallon
> container and filling a larger container,64 bit is taking a 1 gallon
> container and filling the same larger container. the 1 gallon
> container will take less trips. DOUG

>But it's heavier and will tire you out faster. You'll probably end up >with
>tendonitus, too.

Not if the larger container is a gallon....
Anonymous
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a b K Overclocking
December 15, 2004 3:51:13 AM

Archived from groups: alt.comp.hardware.overclocking.amd (More info?)

courseyauto@aol.com (Courseyauto) wrote in
news:20041214183644.08215.00002022@mb-m05.aol.com:

> courseyauto@aol.com (Courseyauto) wrote in
> news:20041214155637.00362.00001843@mb-m17.aol.com:
>
>> Think of it like this. 32 bit like taking a half gallon
>> container and filling a larger container,64 bit is taking a 1 gallon
>> container and filling the same larger container. the 1 gallon
>> container will take less trips. DOUG
>
>>But it's heavier and will tire you out faster. You'll probably end up
>>>with tendonitus, too.
>
> Not if the larger container is a gallon....

64-bits is more than a gallon, however. And even if it weren't, it's well
known that many computer users have Gilligan arms.
Anonymous
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a b K Overclocking
December 15, 2004 4:17:28 AM

Archived from groups: alt.comp.hardware.overclocking.amd (More info?)

courseyauto@aol.com (Courseyauto) wrote in
news:20041214183644.08215.00002022@mb-m05.aol.com:

> courseyauto@aol.com (Courseyauto) wrote in
> news:20041214155637.00362.00001843@mb-m17.aol.com:
>
>> Think of it like this. 32 bit like taking a half gallon
>> container and filling a larger container,64 bit is taking a 1 gallon
>> container and filling the same larger container. the 1 gallon
>> container will take less trips. DOUG
>
>>But it's heavier and will tire you out faster. You'll probably end up
>>>with tendonitus, too.
>
> Not if the larger container is a gallon....

>64-bits is more than a gallon, however. And even if it weren't, it's well
>known that many computer users have Gilligan arms.

I know,they are 4 liters.
December 15, 2004 5:25:38 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

On Mon, 13 Dec 2004 20:31:43 -0600, Jmonahan@ev1.net wrote:

>I have a question about the line of true 64 bit processors. When they
>are running 32 bit software, do they take the instructions, data,
>etc. 2 blocks at a time or is there half of the cpu that is not
>being used?? Where this is leading, is to the question is it better
>to have a super hi speed 32 bit cpu and OC it, or is it better to
>have a 64 bit cpu of less speed. Om that case would they be about
>equal? In other words, is it worth it to buy a 64 bit cpu now, even
>if it is only running 32 bit software and may still be doing that for
>some time??


Opteron and Athlon64 processors are able to run both 64-bit and 32-bit
operating systems and code. Under a 32-bit operating system, including
Linux, Unix, Solaris x86 and Windows, these processors run 32-bit
applications at full speed and full power -- and in many cases, more
efficiently than other x86 processors. When they boot up with a 64-bit
OS, you can mix-and-match 64-bit and 32-bit applications and tools, both
running at full speed. So, 64-bit developers have a huge array of
software available to them, both in terms of the new 64-bit tools and
servers, but also the entire existing base of 32-bit apps. It's
literally the best of both worlds, up and down the stack.

http://www.devx.com/amd/Door/16009
Anonymous
a b à CPUs
a b K Overclocking
December 15, 2004 6:02:16 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

Jmonahan@ev1.net wrote:

> I have a question about the line of true 64 bit processors. When they
> are running 32 bit software, do they take the instructions, data,
> etc. 2 blocks at a time or is there half of the cpu that is not
> being used?? Where this is leading, is to the question is it better
> to have a super hi speed 32 bit cpu and OC it, or is it better to
> have a 64 bit cpu of less speed. Om that case would they be about
> equal? In other words, is it worth it to buy a 64 bit cpu now, even
> if it is only running 32 bit software and may still be doing that for
> some time??

The new processor are backwards compatible instructions with earlier
versions of the architecture. New 64-bit instructions have been added.

So a 64-bit XOR and 16-bit XOR on am Athlon 64 take about the same number of
cpu cycles.


CPU pipelining works on the flow of instructions, and generally not their
width.

gtoomey
Anonymous
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a b K Overclocking
December 15, 2004 12:07:22 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

Lieber Herr Schwantzkopf,


> In fact the base x86
> architecture does use a god awful collection of single purpose registers
> rather than a uniform general purpose register set.

That has always puzzled me. Why in the heck did the micro designers take
that route?

(PS -- also thirty years in computer tech, started out, however, as a
mainframe maintenance tech, considerably lower than a CPU designer)
December 15, 2004 2:23:09 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

"Steve Wolfe" <unt@codon.com> wrote in message
news:328opkF3k439bU1@individual.net...
>> > Tell me why my 32bit 68000 cpu can only address 16MB then (1 clue, it
> has
>> > a 24bit address bus). I really haven't checked, but it's very possible
> to
>> > have a 32bit cpu address more than 4GB. the amount of directly
> addressable
>> > ram is controlled by the size of the address bus, and has nothing to do
>> > with 32, 64, or 128 bit cpu's.
>>
>> The view posted by General Whateverhisnameis may be incorrect, but its an
>> *incredibly* common misconception.
>>
>> I can't count the number of articles I have read that was lyrical about
> the
>> benefits of 64-bit being the increased address space. Presumably the
> author
>> having no clue that it would be perfectly possible to have a 16-bit (let
>> alone 32-bit) processor with a 48-bit or 64-bit address bus.
>
> Here's what's going on: A 32-bit processer really can only address 4
> gigabytes of memory in a single address space. There are hacks like PAE
> that let you put more than 4 gigs in a machine, but a single process can
> only see 4 gigs of memory. That's it, there's no way around it. If you
> disagree, don't argue, try getting a single process to allocate more than
> 4
> gigs on the OS of your choice on a 32-bit processer. Come back when
> you've
> done it.
>
> The A64/Opterons, being 64 bit processers, can address up to a 64-bit
> memory address, which is unfathomably huge. However, I believe that they
> currently have only a 48-bit memory bus, which is still a boat-load of
> memory.
>
> However, going from a 32-bit instruction set to a 64-bit instruction set
> with all other items equal can (and does) incur a slight overhead, as you
> have to pump more bits around to get the same things accomplished. It's
> generally along the lines of 1%-3% real-world performance. However, in
> the
> case of the A64/Opteron, all other items are NOT equal - in 64-bit mode,
> the
> new instruction set allows you to utilize a larger number of registers,
> which gives you a real-world performance BOOST of around 10% in most apps.

Whilst we are on the subject of performance - rather than debates about
address space and number of registers, width etc. - it might be worth
mentioning about the A64 having its memory controller onboard.

Since memory transfers are not being controlled by a separate Northbridge,
the overall latency is much reduced compared with the old XP architecture.
Net effect: Huge memory bandwidth improvement, which obviously boosts
performance considerably too. For example a Sisoft Ram bandwidth (Integer
Buffered iSSE2) score of 4000 is pretty damned fantastic with an Athlon XP.
6000 or more is a walk in the park for an A64. 7000 is fairly easy and 8000
is achievable. HUGE gains in bandwidth.

Chip
December 15, 2004 2:34:59 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

"General Schvantzkoph" <schvantzkoph@yahoo.com> wrote in message
news:p an.2004.12.15.02.17.43.335375@yahoo.com...
>
> It's always been the virtual address space that defined the bitness of a
> CPU architecture.

That's just not correct. Motorola classified the 68000 as 16-bit
microprocessor, yet it had a 24 bit address bus. It had 8 32-bit data
registers and 8 32-bit address registers. By your logic it should have been
called a 32-bit CPU.

Chip
Anonymous
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a b K Overclocking
December 15, 2004 3:26:31 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

Jerry G. wrote:

> Very few
> software's at this time are written in the 64 bit format.
>

Linux & some BDSs have been running 64 bit for years eg MIPS.
There are 64 bit builds of linux for Athlon 64.

gtoomey
Anonymous
a b à CPUs
a b K Overclocking
December 15, 2004 6:51:40 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

"Aardvark J. Bandersnatch, BLT, MP, PBJ, LSMFT" wrote:
>
>> In fact the base x86 architecture does use a god awful collection
>> of single purpose registers rather than a uniform general purpose
>> register set.
>
> That has always puzzled me. Why in the heck did the micro designers
> take that route?

It started with the 8008, which had 7 8 bit registers designated a,
b, c, d, e, h, l. h and l were manipulated only as 8 bits each,
but the combination could be used to address up to a glorious 16k
of external memory. Note that hl pair, introducing register
specialization. Addressing was via a 3 bit field, which could
specify the 7 registers and the indirect via hl address, known as
m. 1/4 of the instructions simply moved data from one register to
another. Arithmetic was done with the a register (accumulator)
implied, which is also a register specialization.

The architecture was continued, for marketing and familiarity
reasons, into the 8080, which added a flags register (8 bit), an sp
register (16 bit) for stack, and instructions to combine the bc,
de, and hl registers into 16 bits and do arithmetic with them.
This was a real computer with 16 bits and an 8 bit path to external
memory. The whole personal computer explosion was really based on
this chip. Now the sp register joined the hl register as
specialized. A set of 16 bit arithmetic instructions was added
using the hl register as the 16 bit accumulator. The 6502 was
competition, and the Z80 was an enhancement (the z80 added more
specialized registers). Other chips had little influence.

The next step was the 8086 (and its 8 bit bussing clone, the
8088). Again, the register architecture was continued, with added
specialized registers and usages. The bc pair became the counting
register for string operations. The si and di indexing registers
(special purpose) were added. The bp (base register for stack
scopes) was added, all specialized. Also the various segment
registers. The adaptations kept the actual code size short yet
greatly expanded the addressing capabilities.

Other major steps were to the 80286 (not really significant) and
the 80386, which is the architectural base of most PC class
machines today.

--
Chuck F (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home.att.net&gt; USE worldnet address!
Anonymous
a b à CPUs
a b K Overclocking
December 15, 2004 9:24:08 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

On Wed, 15 Dec 2004 17:52:04 +0000, VWWall wrote:

> The Z-80 had some features that had to be used by writing ASM code with
> "DB" calls. Adam Osbourne was the only one to offer it in machine.

Radio Shack TRS-80 users would probably disagree with this.

--
Abit KT7-Raid (KT133) Tbred B core CPU @2400MHz (24x100FSB)
http://mysite.verizon.net/res0exft/cpu.htm
Anonymous
a b à CPUs
a b K Overclocking
December 15, 2004 11:36:16 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

> So how do the G5 and G4 chips that Apple uses compare to the the x86?

The Power PC architecture is a clean well designed architecture. IBM had a
research program in the 1970s called the 801 project (after a room number
at Watson Research) which helped define the concept of RISC (reduced
instruction set computer) architectures. The PPC is an outgrowth of 801
program. Stanford had a similar project called MIPS which was
commericialized, and Berkley had the Berkley RISC project which became the
SUN SPARC, Digital did the Alpha architecture. All of those machines,
with the exception of SPARC, consistantly out performed the x86 in each
generation. However performance isn't nearly as important as available
software so the x86 has driven all of the RISC machines, with the
exception of the PPC which survives in the Mac and in IBM servers, into
the grave. What Intel ended up proving is that if you throw enough money
at the problem you can overcome the inherent disadvantages of the
instruction set. Because of the x86's market share Intel can afford to
spend billions on each new processor and more importantly on each new
semiconductor process. The G5 is still faster in scientific applications
(because of it's vastly superior vector instruction set) but it's no
faster than the P4 in most general purpose applications.
Anonymous
a b à CPUs
a b K Overclocking
December 16, 2004 1:40:17 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

"CBFalconer" <cbfalconer@yahoo.com> wrote in message
news:41C05174.DCA35499@yahoo.com...
> "Aardvark J. Bandersnatch, BLT, MP, PBJ, LSMFT" wrote:
>>
>>> In fact the base x86 architecture does use a god awful collection
>>> of single purpose registers rather than a uniform general purpose
>>> register set.
>>
>> That has always puzzled me. Why in the heck did the micro designers
>> take that route?
>
> It started with the 8008, which had 7 8 bit registers designated a,
> b, c, d, e, h, l. h and l were manipulated only as 8 bits each,
> but the combination could be used to address up to a glorious 16k
> of external memory. Note that hl pair, introducing register
> specialization. Addressing was via a 3 bit field, which could
> specify the 7 registers and the indirect via hl address, known as
> m. 1/4 of the instructions simply moved data from one register to
> another. Arithmetic was done with the a register (accumulator)
> implied, which is also a register specialization.
>
> The architecture was continued, for marketing and familiarity
> reasons, into the 8080, which added a flags register (8 bit), an sp
> register (16 bit) for stack, and instructions to combine the bc,
> de, and hl registers into 16 bits and do arithmetic with them.
> This was a real computer with 16 bits and an 8 bit path to external
> memory. The whole personal computer explosion was really based on
> this chip. Now the sp register joined the hl register as
> specialized. A set of 16 bit arithmetic instructions was added
> using the hl register as the 16 bit accumulator. The 6502 was
> competition, and the Z80 was an enhancement (the z80 added more
> specialized registers). Other chips had little influence.
>
> The next step was the 8086 (and its 8 bit bussing clone, the
> 8088). Again, the register architecture was continued, with added
> specialized registers and usages. The bc pair became the counting
> register for string operations. The si and di indexing registers
> (special purpose) were added. The bp (base register for stack
> scopes) was added, all specialized. Also the various segment
> registers. The adaptations kept the actual code size short yet
> greatly expanded the addressing capabilities.

What a kludge! We designed better stuff in hardware classes. Argh.
December 16, 2004 2:08:35 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

"General Schvantzkoph" <schvantzkoph@yahoo.com> wrote in message
news:p an.2004.12.16.01.36.15.382822@yahoo.com...
>
>> So how do the G5 and G4 chips that Apple uses compare to the the x86?
>
> The Power PC architecture is a clean well designed architecture. IBM had a
> research program in the 1970s called the 801 project (after a room number
> at Watson Research) which helped define the concept of RISC (reduced
> instruction set computer) architectures. The PPC is an outgrowth of 801
> program. Stanford had a similar project called MIPS which was
> commericialized, and Berkley had the Berkley RISC project which became the
> SUN SPARC, Digital did the Alpha architecture. All of those machines,
> with the exception of SPARC, consistantly out performed the x86 in each
> generation. However performance isn't nearly as important as available
> software so the x86 has driven all of the RISC machines, with the
> exception of the PPC which survives in the Mac and in IBM servers, into
> the grave. What Intel ended up proving is that if you throw enough money
> at the problem you can overcome the inherent disadvantages of the
> instruction set. Because of the x86's market share Intel can afford to
> spend billions on each new processor and more importantly on each new
> semiconductor process. The G5 is still faster in scientific applications
> (because of it's vastly superior vector instruction set) but it's no
> faster than the P4 in most general purpose applications.


What a shame!
Anonymous
a b à CPUs
a b K Overclocking
December 16, 2004 9:18:36 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

"Aardvark J. Bandersnatch, BLT, MP, PBJ, LSMFT" wrote:
> "CBFalconer" <cbfalconer@yahoo.com> wrote in message
>> "Aardvark J. Bandersnatch, BLT, MP, PBJ, LSMFT" wrote:
>>>
>>>> In fact the base x86 architecture does use a god awful collection
>>>> of single purpose registers rather than a uniform general purpose
>>>> register set.
>>>
>>> That has always puzzled me. Why in the heck did the micro designers
>>> take that route?
>>
>> It started with the 8008, which had 7 8 bit registers designated a,
>> b, c, d, e, h, l. h and l were manipulated only as 8 bits each,
>> but the combination could be used to address up to a glorious 16k
>> of external memory. Note that hl pair, introducing register
>> specialization. Addressing was via a 3 bit field, which could
>> specify the 7 registers and the indirect via hl address, known as
>> m. 1/4 of the instructions simply moved data from one register to
>> another. Arithmetic was done with the a register (accumulator)
>> implied, which is also a register specialization.
>>
>> The architecture was continued, for marketing and familiarity
>> reasons, into the 8080, which added a flags register (8 bit), an sp
>> register (16 bit) for stack, and instructions to combine the bc,
>> de, and hl registers into 16 bits and do arithmetic with them.
>> This was a real computer with 16 bits and an 8 bit path to external
>> memory. The whole personal computer explosion was really based on
>> this chip. Now the sp register joined the hl register as
>> specialized. A set of 16 bit arithmetic instructions was added
>> using the hl register as the 16 bit accumulator. The 6502 was
>> competition, and the Z80 was an enhancement (the z80 added more
>> specialized registers). Other chips had little influence.
>>
>> The next step was the 8086 (and its 8 bit bussing clone, the
>> 8088). Again, the register architecture was continued, with added
>> specialized registers and usages. The bc pair became the counting
>> register for string operations. The si and di indexing registers
>> (special purpose) were added. The bp (base register for stack
>> scopes) was added, all specialized. Also the various segment
>> registers. The adaptations kept the actual code size short yet
>> greatly expanded the addressing capabilities.
>
> What a kludge! We designed better stuff in hardware classes. Argh.

But were they backwards compatible? After writing a few macros, I
could probably run most 8008 source programs on a Pentium.
Remember, at each step, the biggest customer base is the users of
the previous generation. IBM showed the efficiency of this 40
years ago with the 360 instruction set, which preserved binary
compatibility.

Actually I am quite happy to be able to run code from 25 years ago,
for which I have lost the source, yet it executes correctly.

--
Chuck F (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home.att.net&gt; USE worldnet address!
Anonymous
a b à CPUs
a b K Overclocking
December 16, 2004 3:47:54 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

General Schvantzkoph <schvantzkoph@yahoo.com> wrote in
news:p an.2004.12.15.16.47.41.662107@yahoo.com:

>
> IBM wanted to use the 68K but Motorola was late and Intel had the 8088
> ready to go. Nobody thought the original PC was going to be anything
> more than a one-of type of machine, so it didn't matter that it used an
> awful processor. The 8088 was better than the Z80 which powered the
> competing CP/M machines of the time and that's all that mattered. If IBM
> had thought that the PC was going to become a standard that would last
> for decades they never would have allowed Microsoft to own the operating
> system and they probably would have used a microprocessor of their own
> rather than use an Intel part. Even Intel didn't think the x86
> architecture was going to last, they were working on a part called the
> 432 which they thought was the machine of the future. The 432 was a
> fiasco. The 432 was what was called a capability based architecture, it
> used hardware to manage objects. It was a terrible idea that was way
> beyond the technology of the time. Intel tried to kill the x86 again in
> the late 80s with the i860 which was a RISC machine of sorts. The i860
> was more successful than the 432, it was a pretty good DSP and it found
> it's way into a lot of parallel processors. Intel sold thousands of them
> which means they lost their shirts on it because a chip company needs to
> sell millions of parts not thousands, but at least it wasn't the
> embarassment that the 432 had been. The latest attempt to kill the x86
> was the Itanium which is been even less successful than the i860. Intel
> hasn't officially thrown in the towel on the Itanium but everyone else
> has. Microsoft isn't supporting it in their upcoming clustering version
> of XP Server which is the first step towards dropping support
> altogether. Intel has a couple more generations of Itaniums still on
> their roadmap but they no longer talk about desktop Itaniums, only high
> end servers. So the x86, a baby so ugly that it's own mother has tried
> to drown it three time, continues to live on as the x86-64 and will be
> with us for years to come.
>

Way back when I heard that IBM wanted assurances of backward compatibility in
future micorprocessors. The claim was that Intel said yes and Motorola said
no. Can you comment about this?

TIA
Anonymous
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a b K Overclocking
December 16, 2004 3:47:55 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

On Thu, 16 Dec 2004 12:47:54 +0000, John Smithe wrote:

> General Schvantzkoph <schvantzkoph@yahoo.com> wrote in
> news:p an.2004.12.15.16.47.41.662107@yahoo.com:
>
>>
>> IBM wanted to use the 68K but Motorola was late and Intel had the 8088
>> ready to go. Nobody thought the original PC was going to be anything
>> more than a one-of type of machine, so it didn't matter that it used an
>> awful processor. The 8088 was better than the Z80 which powered the
>> competing CP/M machines of the time and that's all that mattered. If IBM
>> had thought that the PC was going to become a standard that would last
>> for decades they never would have allowed Microsoft to own the operating
>> system and they probably would have used a microprocessor of their own
>> rather than use an Intel part. Even Intel didn't think the x86
>> architecture was going to last, they were working on a part called the
>> 432 which they thought was the machine of the future. The 432 was a
>> fiasco. The 432 was what was called a capability based architecture, it
>> used hardware to manage objects. It was a terrible idea that was way
>> beyond the technology of the time. Intel tried to kill the x86 again in
>> the late 80s with the i860 which was a RISC machine of sorts. The i860
>> was more successful than the 432, it was a pretty good DSP and it found
>> it's way into a lot of parallel processors. Intel sold thousands of them
>> which means they lost their shirts on it because a chip company needs to
>> sell millions of parts not thousands, but at least it wasn't the
>> embarassment that the 432 had been. The latest attempt to kill the x86
>> was the Itanium which is been even less successful than the i860. Intel
>> hasn't officially thrown in the towel on the Itanium but everyone else
>> has. Microsoft isn't supporting it in their upcoming clustering version
>> of XP Server which is the first step towards dropping support
>> altogether. Intel has a couple more generations of Itaniums still on
>> their roadmap but they no longer talk about desktop Itaniums, only high
>> end servers. So the x86, a baby so ugly that it's own mother has tried
>> to drown it three time, continues to live on as the x86-64 and will be
>> with us for years to come.
>>
>
> Way back when I heard that IBM wanted assurances of backward compatibility in
> future micorprocessors. The claim was that Intel said yes and Motorola said
> no. Can you comment about this?
>
> TIA

I doubt that they were thinking about backward compatibility when they did
the original PC. The PC was an experiment to see if IBM could get
something out the door quickly and cheaply like a startup. At the time
Apple was taking off with the Apple II and IBM wanted to show that they
could compete in that market too. None of the established computer
companies was enthusistic about personal computers because they didn't see
any way of making any money selling cheap machines. IBM was making
billions selling multi-million dollar mainframes, how could they possible
make as much selling thousand dollar machines (the original PC was around
$3000). Never the less they wanted to cover their bets just in case
personal computers became important. I remember talking to an engineer
from the PC division at a conference in the early 80s. He said that they
had been forbidden to use any IBM resources to build the PC, they had to
go outside for everything just like a startup would have to do. The result
was the PC which used an Intel processor and Microsoft operating system.
Like a startup they were primarily concerned with getting it out the door
as quickly as possible. Motorola had slipped the 68K's schedule by 6
months so they used the Intel 8088 instead. I'm sure that they were
thinking that they could always switch processors in a future machine.
What they didn't count on was the huge success of the PC and more
importantly the rise of the PC clones which happened almost immediately.
Prior to the PC it wasn't practical to clone someone elses machine. Data
General and DEC sued the makers of Nova and PDP 11 clones out of business.
There were a couple of Japanese clones of the 370 but they never acheived
enough market share to really trouble IBM. The PC was different because it
was possible for a smaller and quicker competitor to build a truely
identical machine. Compaq came out very soon after the launch of the PC.
It was the clone makers that locked in the architecture and took away IBMs
ability to change the architecture. If you remember the machine after the
AT used an IBM proprietary bus instead of the AT bus. It was IBM's attempt
to recapture control of the PC, it failed. IBM was never again able to
influence the course of PC development. As it turned out they were right
to doubt that they could make money with PCs, they never did. Last weeks
sale of the PC division to Lenovo puts and end to an era. IBM's
competitors from that era are almost all gone now, Digital, Data General,
Prime, Control Data, none of them could survive in the PC era. Only HP
remains and they make almost all of their money from ink, their PCs are
probably a near breakeven business as they were for IBM.
Anonymous
a b à CPUs
a b K Overclocking
December 16, 2004 6:55:09 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

CBFalconer <cbfalconer@yahoo.com> wrote in news:41C122BE.6393B0B5
@yahoo.com:

> Actually I am quite happy to be able to run code from 25 years ago,
> for which I have lost the source, yet it executes correctly.

Not to argue with your point, which is correct, but you don't really need a
compatible instruction set for 25 year-old code--you can emulate. Its
really a matter of being able to run the apps you are using now when you
change hardware. Apple did a pretty good job making current 68k apps run on
the PPC, too.
Anonymous
a b à CPUs
a b K Overclocking
December 17, 2004 2:54:38 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

CBFalconer wrote:

> Actually I am quite happy to be able to run code from 25 years ago,
> for which I have lost the source, yet it executes correctly.
>
It's even more amazing how the BIOS can still accommodate old code.
I've got stuff that was originally ASM for a X80 CPU, that still works
on Win98 in a DOS window. Most was written in "C", (K&R style and
compiled with TurboC). I have one program called "Circus", that uses
channel 2 of the present CMOS version of the old programmable timer. It
still plays calliope music through the PC speaker, if you can find a
case with a real speaker. The evolution through ever larger HD's has
been interesting, and the 48bit BIOS's look like they'll keep up with
new HD's for awhile! (WD giveth and MS taketh away.)

Virg Wall (Old CP/M ASM programmer.)
Anonymous
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a b K Overclocking
December 17, 2004 3:46:59 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

"Mitch Crane" <a-one@a-two.a-three> wrote in message
news:Xns95C16F194CDDB616F6E656174776F6174@63.223.5.95...
> CBFalconer <cbfalconer@yahoo.com> wrote in news:41C122BE.6393B0B5
> @yahoo.com:
>
>> Actually I am quite happy to be able to run code from 25 years ago,
>> for which I have lost the source, yet it executes correctly.
>
> Not to argue with your point, which is correct, but you don't really need
> a
> compatible instruction set for 25 year-old code--you can emulate.

Eggzackly.
Anonymous
a b à CPUs
a b K Overclocking
December 17, 2004 9:13:57 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

"Aardvark J. Bandersnatch, BLT, MP, PBJ, LSMFT" wrote:
> "Mitch Crane" <a-one@a-two.a-three> wrote in message
>> CBFalconer <cbfalconer@yahoo.com> wrote in news:
>>
>>> Actually I am quite happy to be able to run code from 25 years ago,
>>> for which I have lost the source, yet it executes correctly.
>>
>> Not to argue with your point, which is correct, but you don't really
>> need a compatible instruction set for 25 year-old code--you can
>> emulate.
>
> Eggzackly.

Possible, but that 25 year old code written in assembly seems to
handle anything in roughly zero clock time. Loading is of a paltry
5 or 10 kb, if that, no problem with locality and caches, etc.

--
Chuck F (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home.att.net&gt; USE worldnet address!
Anonymous
a b à CPUs
a b K Overclocking
December 30, 2004 1:57:45 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

There are already 64 bit versions of Windows XP and Windows 2003. Do you
know what 32 bit or 64 bit processing is for?
It is the amount of memory that can be accessed. 2 to 32th power or 2 to
64th power of addressable virtual memory. This is useful for sites running
terabyte size databases. It doesn't really buy you any additional
processing power, because just the operating system can address 2 to the
64th power of virtual memory, do you have a database that size. Also, the
exponent means that certain virtual memory management modules are going to
be loaded farther into virtual memory. I know this from having been a
mainframe (IBM). If PC manufacturers wanted to make their processor
motherboards faster, they should have multiple IO paths to the disk drives.
If one path is busy to a disk, and you have another disk then another path
is used. This would reduce IO load and pass data faster through to the
processor. I also use a Promise raid card now, with its own IO processing
ability to offload IO operations from the cpu.

I hope AMD comes out with at least one if not two more faster Socket A(462)
processors, because 32 bit software is going to be here a lot longer.

Save the money. Look for fast IO mobo, and go to a SATA raid with its own
IO processor.

BTW just doing normal processing you would probably use very infrequently
the full 2 to 32d power of virtual memory because you are not running
programs requiring that much virtual memory. Half of the cpu is being used,
but it is only running around looking for something to do.

<Jmonahan@ev1.net> wrote in message
news:qljsr05mpgh8mk8i3e3rlvs64ad7jghnhp@4ax.com...
>I have a question about the line of true 64 bit processors. When they
> are running 32 bit software, do they take the instructions, data,
> etc. 2 blocks at a time or is there half of the cpu that is not
> being used?? Where this is leading, is to the question is it better
> to have a super hi speed 32 bit cpu and OC it, or is it better to
> have a 64 bit cpu of less speed. Om that case would they be about
> equal? In other words, is it worth it to buy a 64 bit cpu now, even
> if it is only running 32 bit software and may still be doing that for
> some time??
Anonymous
a b à CPUs
a b K Overclocking
December 30, 2004 3:44:48 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

"John F. Regus" <jfregus@ix.netcom.com> wrote in
news:JaRAd.2165$Cc.679@newsread3.news.pas.earthlink.net:

> There are already 64 bit versions of Windows XP and Windows 2003. Do
> you know what 32 bit or 64 bit processing is for?
> It is the amount of memory that can be accessed.

I keep reading that, but it seems bogus to me. Are you saying that these
64-bit processors only have 64-bit address registers and nothing for data?

Assuming it can do each operation in the same clock cycles, a 64 bit
operation should be faster than two 32-bit operations on the same data. So
there should be situations where this could be taken advantage of by 64-bit
software. Otherwise we may as well have stuck to 8-bit registers and an 8-
bit data path.
Anonymous
a b à CPUs
a b K Overclocking
December 30, 2004 9:12:39 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

On Thu, 30 Dec 2004 10:57:45 GMT, "John F. Regus"
<jfregus@ix.netcom.com> wrote:

>There are already 64 bit versions of Windows XP and Windows 2003. Do you
>know what 32 bit or 64 bit processing is for?
>It is the amount of memory that can be accessed. 2 to 32th power or 2 to
>64th power of addressable virtual memory. This is useful for sites running
>terabyte size databases. It doesn't really buy you any additional
>processing power, because just the operating system can address 2 to the
>64th power of virtual memory, do you have a database that size.

There have been real performance benefits seen from 64bit,
one does not have to speculate, just benchmarking is enough.


>Also, the
>exponent means that certain virtual memory management modules are going to
>be loaded farther into virtual memory. I know this from having been a
>mainframe (IBM).

I'd keep quiet about that, if the MAN realizes you've gone
organic he'll hunt you down. ;-)

>If PC manufacturers wanted to make their processor
>motherboards faster, they should have multiple IO paths to the disk drives.
>If one path is busy to a disk, and you have another disk then another path
>is used. This would reduce IO load and pass data faster through to the
>processor. I also use a Promise raid card now, with its own IO processing
>ability to offload IO operations from the cpu.

That was true for awhile, but the CPU is not a bottleneck
anymore, and with DMA you're looking at more of a PCI bus
bottleneck (up until PCI Express) and physical (mechanical)
storage medium bottleneck.

>
>I hope AMD comes out with at least one if not two more faster Socket A(462)
>processors, because 32 bit software is going to be here a lot longer.

As an upgrade path for current socket A motherboard owners
it seems a good idea, but otherwise not. Athlon 64 is
faster at 32 bit due to integral memory controller. If one
doesn't want to pay the overhead for 64 bit, there are 32
bit Semprons. There is no advantage to socket A which would
entice one to buy a motherboard for that platform except the
maturity of the technology, maturity of the motherboards,
their bios, and the (currently) lower cost.
Performance-wise socket A is dead already.
December 31, 2004 7:44:19 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware (More info?)

"John F. Regus" <jfregus@ix.netcom.com> wrote in message
news:JaRAd.2165$Cc.679@newsread3.news.pas.earthlink.net...
> There are already 64 bit versions of Windows XP and Windows 2003. Do you
> know what 32 bit or 64 bit processing is for?
> It is the amount of memory that can be accessed. 2 to 32th power or 2 to
> 64th power of addressable virtual memory.

Did you read ANY of this thread before posting this?

Not only has it been discussed *extensively* already, its also not really
correct. Yes, you can address more memory with a larger address registers
and address bus. But what about the data registers and data bus? What
about the fact that you can grab 8 bytes of data in one memory access and
process all 8 bytes at once - as opposed to only 4 bytes in a 32-bit
architecture?

I suggest you read the rest of the thread before typing again.

Chip
!