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HELP! 64bit & 32bit what's the difference?

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June 13, 2006 9:29:27 AM

Eh.. may i ask what are the advantage of a 64 bit processor?

& what windows XP64 has to offer compared to the windows XP32? :roll:

More about : 64bit 32bit difference

June 13, 2006 9:40:14 AM

Quote:
Eh.. may i ask what are the advantage of a 64 bit processor?

& what windows XP64 has to offer compared to the windows XP32? :roll:

There are differences between different 64bit architectures. The advantage of 64bit x86 computing we have not seen yet. It lets widther memory addressing and allocation and opens oportunities for better virtualization, but we have not tasted its benefits yet.
While there is no 64bit software available for general purposes users I consider that we have no adventage of 64bit processing capable x86 CPUs. Many fanboys will argue about the 0.05% x86-64 software that is available today and the Linux performance boost, but that is rediculous. We even don't have a driver support for the 64bit x86 OSes available for some time.
June 13, 2006 10:36:47 AM

Extra general purpose and SSE registers.
Related resources
June 13, 2006 11:30:28 AM

Quote:
Extra general purpose and SSE registers.

The extra GP & XMM and the unvisible scratch registers are not features that come with the transition from 32bit to 64bit. They are features that AMD added to K7. It is not the case with Pentium4, Intel implemented EM64T without these architectural improvements. The 64bit capability is achieved with extending the data paths and registers from 32bit to 64bit and the address size to 64bit. Larger address size means better virtualization oportunities. The 32bit allows virtual memory and 4GB addressing. The 64bit allows higher physical and virtual addressing(40bits & 48bits), NX, 1bit executable page control, virtualization Intel & AMD (I don't know how many bits are involved) and maybe some other features.

Anyway the topic is not about x86-64, its about the advantages of 64bit over 32bit computing.
June 13, 2006 11:47:18 AM

More memory address space and easier/quicker to get high-precision mathematic results.

One tradeoff is larger program footprint due to addresses being 8 bytes instead of 4. Not usually a huge difference but it's there.
June 13, 2006 12:31:19 PM

On private computers theres no advantage, Id even say theres a disadvantage because of the software/drivers the user would have to bother with.
June 13, 2006 12:38:23 PM

Quote:

& what windows XP64 has to offer compared to the windows XP32? :roll:


You don't see any benifit with Windows XP64 yet because none of the general apps are written in 64-bit. I thing when (if) the new version of Windows come out, we will start to see more apps written in 64-bit. You will changes. But as in general, more advance, more resources. This will be simular to the transision from Windows 3.1 to Windows 95 if you remember...
June 13, 2006 12:40:27 PM

Quote:
Eh.. may i ask what are the advantage of a 64 bit processor?

& what windows XP64 has to offer compared to the windows XP32? :roll:


64 bit computing allows for more computations, therefore allowing better frames per second in games.

Windows x64 however, has problematic drivers and serious problems on occasion (sp?). Wait for Vista's 64 bit edition.
June 13, 2006 12:52:14 PM

Quote:
This will be simular to the transision from Windows 3.1 to Windows 95 if you remember...

With Windows95 & Windows95 32bit.


Quote:
64 bit computing allows for more computations, therefore allowing better frames per second in games.

How it allows more computations?
Can you be more specific?
June 13, 2006 1:31:30 PM

When the 386 came out way back when in the 1980's (1986 I believe) it was a 32 bit CPU that could (in theory) address 4 GB of RAM... 4 GB of RAM sounded like science fiction to the people in the 80's, but now we're not too far away from seeing the 4 GB desktop computer. Just like the 640k RAM limit and the 2.1 GB FAT16 limit, this one's time has come... 64 bit processors don't have this 4 GB limit. Other than that, I don't see any near-term benefits from making the jump.
June 13, 2006 1:38:35 PM

Quote:
This will be simular to the transision from Windows 3.1 to Windows 95 if you remember...

With Windows95 & Windows95 32bit.


Quote:
64 bit computing allows for more computations, therefore allowing better frames per second in games.

How it allows more computations?
Can you be more specific?

Lets say for example you are adding two doubles (double precision numbers). Each double is 64 bits the 32 bit CPU must address 64 bits of memory space. Since it must address each space individually your memory seek time is double what a 64 bit would achieve. Since the 64 bit only has to perform one single seek.

Since the CPU spends less time waiting for the memory to provide it information, the CPU time is better utilized for doing actual work. Hence you get better performance.
June 13, 2006 1:49:13 PM

Quote:
Eh.. may i ask what are the advantage of a 64 bit processor?

& what windows XP64 has to offer compared to the windows XP32? :roll:


A 32 bit system can access about 4 gigabytes of ram. A 64 bit system can access about 17,179,869,184 gigabytes of ram, an increase by a factor of about 4 billion (reference from Wikipedia). That makes for a potential increase of computer efficiency and speed that is almost beyond comprehension.

As a more practical matter, very few programs have been written to take advantage of the increases of ability. XP64 Pro was poorly written, has few drivers for home use, has had little in the way of support from Microsoft, and little in the way of support from software companies. It has great potential, but that potential was never utilitzed.

One of the many problems with Vista has been the question of support, both from Microsoft and from the software industry. The 32 bit version of XP has never been fully utilized, with the familiar occurance that only 2 gig of ram is really used, much less the 4 gig that is available. How much of a 64 bit system's potential will get used? That's impossible to say at the moment, but I would guess that it may be years before we will see anything major on the consumer side of things.
June 13, 2006 2:12:19 PM

Quote:


While there is no 64bit software available for general purposes users I consider that we have no adventage of 64bit processing capable x86 CPUs. Many fanboys will argue about the 0.05% x86-64 software that is available today and the Linux performance boost, but that is rediculous. We even don't have a driver support for the 64bit x86 OSes available for some time.


I just wanted to say that i'm running linux amd64 for 2 years now, and everything works very fine. And more people than you think use it.As for the driver support i can only say that all my hardware works, in a 64bit kernel. So the driver support is definitly there
June 13, 2006 3:27:46 PM

Quote:
Lets say for example you are adding two doubles (double precision numbers). Each double is 64 bits the 32 bit CPU must address 64 bits of memory space.

The 64bit CPU must address 64bits for a 64bit value also.

Quote:
Since it must address each space individually your memory seek time is double what a 64 bit would achieve. Since the 64 bit only has to perform one single seek.

Every CPU must address every double individualy. You are missing the concept, memory addressing is not memory capacity or space.

Quote:
Since the CPU spends less time waiting for the memory to provide it information, the CPU time is better utilized for doing actual work. Hence you get better performance.

What do you mean?
The CPU time spended on waiting for memory is dependend only on the memory controller and bus efficiency, latency and bandwidth and RAM bandwidth and latency. It has nothing with how many bit is your CPU. For example, all K8 are 64bit but there are 3 variants of the IMC: 64bit DDR, 128bit DDR and 128bit DDR2, abd all are not same efficient.
June 13, 2006 4:43:52 PM

Quote:
Lets say for example you are adding two doubles (double precision numbers). Each double is 64 bits the 32 bit CPU must address 64 bits of memory space.

The 64bit CPU must address 64bits for a 64bit value also.

Quote:
Since it must address each space individually your memory seek time is double what a 64 bit would achieve. Since the 64 bit only has to perform one single seek.

Every CPU must address every double individualy. You are missing the concept, memory addressing is not memory capacity or space.

Quote:
Since the CPU spends less time waiting for the memory to provide it information, the CPU time is better utilized for doing actual work. Hence you get better performance.

What do you mean?
The CPU time spended on waiting for memory is dependend only on the memory controller and bus efficiency, latency and bandwidth and RAM bandwidth and latency. It has nothing with how many bit is your CPU. For example, all K8 are 64bit but there are 3 variants of the IMC: 64bit DDR, 128bit DDR and 128bit DDR2, abd all are not same efficient.

I have people who try to tell me that they "can see" or "really
tell" that Windows 64 is faster and that thier games run faster/look better.

I keep telling them it is all in thier minds!

I have no use for an OS that has issues running software,or problems with hardware due to lack of drivers...no matter if the driver support is better than years ago.

I also will not even bother to d/l Vista for free as I both have no use for it and really dislike the DRM in the core. The fact that it will have DX 10 is a useless selling point and I think will be so for the next 10 years.

Being able to run more than 4GB of ram is the saleing point and even the new computers I build have 2 GB....the older ones with 1GB never use it all.

Z
June 13, 2006 4:51:49 PM

I believe what he's getting after here is that, for high-precision math (i.e. with 64-bit numbers) 64-bit processors running in 64-bit mode are faster due to multibple reasons:

1) Only 1 memory fetch to get the 64-bit value to work on (per number, of course)

2) No need to run multiple passes on the number(s) in order to do the work, i.e.
[code:1:a657c277be]64-bit add:
64-bit System:
fetch A
fetch B
add64 A,B

32-bit System:
fetch A1 //32 LSB
fetch A2 //32 MSB
fetch B1 //32 LSB
fetch B2 //32 MSB
add32 A1,B1 //add the "bottom half"
add32_w_carry A2,B2 //add the "top half" with carry[/code:1:a657c277be]

As I'm sure others will point out, this is very much a simplification, but the idea remains the same.

And, of course, the increased memory space is really nice too (as many have mentioned).

Now we just need to dump legacy BIOS and the 4G "memory hole" issue will go away.
June 13, 2006 6:32:27 PM

bmouring: That is exactly what I was trying to get at.

gOJDO: Regarding the last paragraph of what you said. I'm not talking about 64 bit DDR, 128 bit DDR. Yes there is a performance difference between different types of memory. But the example I gave is assuming that everything else is the same, only difference being the CPU. Regardless of the speed of the memory if you have to do two read operations you will always have twice the latency.
a c 471 à CPUs
June 13, 2006 11:28:50 PM

Quote:
Eh.. may i ask what are the advantage of a 64 bit processor?

& what windows XP64 has to offer compared to the windows XP32? :roll:


Many people have already given their opinions about a 64-bit CPU and 64-bit OS.

I'll just state that you really need to go out of your way to get a 32-bit CPU nowadays. Sure, you can buy an old 32-bit Sempron, but it will give you pretty poor performance compared to the other CPUs, because AMD and Intel simply stopped making fast 32-bit CPUs.

Don't worry about 32-bit vs. 64-bit yet. Just buy whatever CPU you can afford. As for a 64-bit OS, sure it sounds nice, but unless there's a 64-bit program that you must absolutely have, or you need to brag to your friends that you are running a 64-bit OS, you can forget about Windows XP 64. Windows Vista? Wait for SP1 to plug up any security holes and bugs.
June 14, 2006 12:10:49 AM

I have two virtually identical systems, one with 32bit the other 64, I've had no probs playing all the same games and using all the same apps on either. I have only noticed a speed increase when a clean install is done and then ie starts noticably quicker, that's it, doesn't browse quicker or anything, just pops up quicker. I've had zero driver issues, x800, 3700+, highpoint rocketraid 2320 w/4 wd3200's, pioneer dvd, silverstone case with iMon.

No noticable difference in frame rates, but I haven't used fraps to really test that.
June 14, 2006 12:19:29 AM

He did ask about what 64bit XP offers over 32bit. :wink:
June 14, 2006 2:28:04 AM

I read on wikipedia that 64bit works best on larger hardisk. Why is that so?

and according to the replies here, the software must support 64bit then there's a advatage. Besides the winXP64, what other software support this? Does Adobe photoshop CS2 support it? And what games support 64bit?

sorry for my poor use of english ><
June 14, 2006 2:43:14 AM

When I installed XP x64 Edition (free 6 month evaluation from microsoft that you can get too) and tested the CPU with SiSandra 2005 benchmarking software, my 64bit CPU processing scores went up 15 and 20% immediately.
Make of it what you will. Just reporting my experience with it.

-I used no 64bit apps and only had 1GBs of ram.
-Drivers were all easy to find and download.
-There were only less options for the different applications that I like such as antivirus and anti-spyware. But this will change almost overnight once Vista releases to corporations in November.
-I am running x64 now for everything I do, including this message and I will make a seamless transition to Vista once it is released.
June 14, 2006 3:01:05 AM

Quote:
I read on wikipedia that 64bit works best on larger hardisk. Why is that so?

and according to the replies here, the software must support 64bit then there's a advatage. Besides the winXP64, what other software support this? Does Adobe photoshop CS2 support it? And what games support 64bit?

sorry for my poor use of english ><


A larger hard disc is required mainly because the program itself is a bit larger and the file size is larger. Don't get too hung up on that point. Any hard disc 60 gig or larger will do. Besides, if you find yourself needing more room, just buy another hard disc and add it to your system.

Yes, the software must be written in 64 bit code to take full advantage. There's several games and applications that are written in 32 bit code, but ported to 64 bit. These may run faster, but then again, may not. As time goes on, an increasing number of games and such will be written in a native 64 bit code. Then there should be real speed increases. Until that happens, don't worry too much about it.
June 14, 2006 5:22:29 AM

Quote:
and according to the replies here, the software must support 64bit then there's a advatage. Besides the winXP64, what other software support this? Does Adobe photoshop CS2 support it? And what games support 64bit?


Very few consumer apps are 64-bit and few need to be. Databases are the first apps ported to 64-bit OSes then 3D renderers (i.e Mental Ray / XSI / RenderMan are 64-bit) because these apps eat GBs of memory.

I don't think CS2 is 64-bit - it's also not fully HDRI (i.e floating point buffers - 128-bit RGBA) which kinda blows for high-end film work.
June 14, 2006 5:25:57 AM

Quote:
Now we just need to dump legacy BIOS ...


Hell ya! Give me EFI - so we can ditch Windows and use another OS without driver/hardware issues!

I can't believe were in 2006 and still stuck with the IBM BIOS... argh.
June 14, 2006 12:00:43 PM

Quote:
Not talking about x86-64 or any other RISC 64-bit processors. Just 64-bit processors in general.
The main (and maybe the only) advantage with 64-bit is vastly larger memory addressing and possibly, less overhead.



Don't forget wider instruction streams and larger structures.
June 14, 2006 11:40:29 PM

That's pretty much it. 64bit processing just allows larger memory addressing.

The difference is minor right now because most people don't have a need for more than 2GB's of memory and no one here will need to access to what, 2 perabytes of memory?

well whatever "18446744073709551616" this number is is the maximum amount of RAM.

Quote:
Not talking about x86-64 or any other RISC 64-bit processors. Just 64-bit processors in general.
The main (and maybe the only) advantage with 64-bit is vastly larger memory addressing and possibly, less overhead.
June 15, 2006 12:47:01 AM

Quote:

I also will not even bother to d/l Vista for free as I both have no use for it and really dislike the DRM in the core. The fact that it will have DX 10 is a useless selling point and I think will be so for the next 10 years.

Being able to run more than 4GB of ram is the saleing point and even the new computers I build have 2 GB....the older ones with 1GB never use it all.

Z


I bet DX10 features will be in virtually ever new game within 3 years. Look at DX9. It came out at the end of 2002 and now most games have features that only work with DX9 (probalby 9.0c).

As for ram, there are games that work better with 2gb than 1gb. For general desktop useage, you probably could live with 512mb and could easilly live with 1gb, but games, photoshop and video editing all love lots of ram.
June 15, 2006 1:09:43 AM

I hope you all realise that Windows Vista will be available in both 32bit AND 64bit editions. So the move to Windows Vista over the next few years WON'T necessarily change all mainstream computing over to 64bit Operating Systems.

However, I think all modern processors are 64bit capable now (Athlon64's and Intel Core), so the uptake of the 64bit OS should be easier and manufacturers are much more likely to invest in 64bit drivers for their hardware as it'll be a lot more mainstream than during XP's reign.

I think the NEXT consumer version of Windows AFTER Vista might be 64bit only. Until then, I wouldn't go to any extreme lengths to live the 64bit lifestyle right now.

32bit to 64bit is a much bigger shift than a software change like DirectX10. Although I heard DirectX10 might not be backwards compatible like all current DirectX versions are ... then again, I heard that DirectX10 will be able to exist side by side with an installed DirectX9 for those that would need backwards compatibility.
June 15, 2006 1:50:39 AM

Quote:
That's pretty much it. 64bit processing just allows larger memory addressing.

The difference is minor right now because most people don't have a need for more than 2GB's of memory and no one here will need to access to what, 2 perabytes of memory?

well whatever "18446744073709551616" this number is is the maximum amount of RAM.


Gah! Grrrrrrrr!

It frustrates me to no end to see otherwise intelligent techs make this mistake over and over and over again.

here is the skinny. There are many different things that someone could be referring to when they say 64 bit.

The most common two however are the memory addressing and the GPR (general purpose registers).

When someone is talking about a 64 bit CPU with no other qualifications what they mean is a CPU that supports 64 bit code and therefore uses 64 bits of general purpose registers.

Pretty much all 64 bit processors ALSO have a 64 bit memory address bus but that is not what is meant by 64 bit processing.

Lets explain it this way. We have used Win32 for many years. This is 32 bit code and works on all 32 bit compatible processors. Over this time our memory addressing has increased in various CPU models. We never once needed to revise our code or operating systems. Do you know why? Because they don't care. The only reason we need new drivers, OSs, and code is because we are using more registers to get things done.

If you don't believe me, then go take an assembly class. That will get you straightened out real quick.
June 15, 2006 2:21:53 PM

Quote:
That's pretty much it. 64bit processing just allows larger memory addressing.

The difference is minor right now because most people don't have a need for more than 2GB's of memory and no one here will need to access to what, 2 perabytes of memory?

well whatever "18446744073709551616" this number is is the maximum amount of RAM.

Not talking about x86-64 or any other RISC 64-bit processors. Just 64-bit processors in general.
The main (and maybe the only) advantage with 64-bit is vastly larger memory addressing and possibly, less overhead.


You forget that scientific/professional software, encoding and other software benefit more than from the increased memory: 64bit operations are common in renderings and you can see right now that many 64 bit renderers get 30-40% performance boost from this.
June 17, 2006 8:03:02 AM

if there are so little software that supports 64bit on personal computers y did they even make the shift over from server technology to home-base PC?
June 17, 2006 8:21:04 AM

Quote:
if there are so little software that supports 64bit on personal computers y did they even make the shift over from server technology to home-base PC?

Because server technology increasingly affects our everyday life as high speed LAN and internet are getting the standard. The ability to better handle large file transfers is getting more and more important and with a 64 bit system you have many benefits. But, definitely, I wouldn't call it SERVER TECHNOLOGY just because it's extensively used by servers now.
On the other hand, there are more 64bit software than you may think: scientific and graphical software are there and microsoft is going to fully support 64 bit architecture with the next releases.
I think that in a year or so, the 64bit future will fully, at last; whatch not to be left out of it :D 
June 17, 2006 8:21:37 AM

Because AMD needed a catchy marketing name.
June 17, 2006 8:31:07 AM

Quote:
Because AMD needed a catchy marketing name.


I was just rendering some interiors and got them 47% faster than with the 32bit version of the software I use, enough to fool any single core CPU operating in 32 bit mode: think it's a bit more than a catchy marketing name!
June 17, 2006 8:51:01 AM

Quote:
Because AMD needed a catchy marketing name.


I was just rendering some interiors and got them 47% faster than with the 32bit version of the software I use, enough to fool any single core CPU operating in 32 bit mode: think it's a bit more than a catchy marketing name!

I never said it didn't offer greater performance, AMD needed something to stand out from Intel and define their own brand. "AMD64" is their slogan now and they throw it EVERYWHERE. No, we didn't NEED it, and sure, it's nice to have, but how much software is there REALLY for 64-bit? It's been years since the initial launch and still we have little to go on.

Trust me, with the numbering scheme they were using, it was the marketing department that decided they needed something 'revolutionary', and the engineers said "hey check this out".
June 17, 2006 10:20:25 AM

Quote:
Because server technology increasingly affects our everyday life as high speed LAN and internet are getting the standard. The ability to better handle large file transfers is getting more and more important and with a 64 bit system you have many benefits. But, definitely, I wouldn't call it SERVER TECHNOLOGY just because it's extensively used by servers now.
On the other hand, there are more 64bit software than you may think: scientific and graphical software are there and microsoft is going to fully support 64 bit architecture with the next releases.
I think that in a year or so, the 64bit future will fully, at last; whatch not to be left out of it :D 


'server technology' as in once upon a time 64bit WAS created for servers.
Anyway, u mean if i hav a 64bit processor and 64bit OS transefering of large files from one hd to another is alot faster?
June 17, 2006 12:05:26 PM

Quote:
Because server technology increasingly affects our everyday life as high speed LAN and internet are getting the standard. The ability to better handle large file transfers is getting more and more important and with a 64 bit system you have many benefits. But, definitely, I wouldn't call it SERVER TECHNOLOGY just because it's extensively used by servers now.
On the other hand, there are more 64bit software than you may think: scientific and graphical software are there and microsoft is going to fully support 64 bit architecture with the next releases.
I think that in a year or so, the 64bit future will fully, at last; whatch not to be left out of it :D 


'server technology' as in once upon a time 64bit WAS created for servers.
Anyway, u mean if i hav a 64bit processor and 64bit OS transefering of large files from one hd to another is alot faster?

So they say. At least on my system: XP-32 transferred a 2.5 GB folder in 2min18sec while XP-64 did it in 1min 46sec that's a pretty good difference!
June 17, 2006 12:13:01 PM

Quote:
Because AMD needed a catchy marketing name.


I was just rendering some interiors and got them 47% faster than with the 32bit version of the software I use, enough to fool any single core CPU operating in 32 bit mode: think it's a bit more than a catchy marketing name!

I never said it didn't offer greater performance, AMD needed something to stand out from Intel and define their own brand. "AMD64" is their slogan now and they throw it EVERYWHERE. No, we didn't NEED it, and sure, it's nice to have, but how much software is there REALLY for 64-bit? It's been years since the initial launch and still we have little to go on.

Trust me, with the numbering scheme they were using, it was the marketing department that decided they needed something 'revolutionary', and the engineers said "hey check this out".

Guess you're right, and they're right too. I'm not what they call a fanboy here but at least in marketing, AMD has done better than intel the last years.
Everyone complainet about new numberings at the beginning but they've proven to be right since even intel left the raw GHz numberings. But if AMDs system is little less appealing in terms of CPU speed, it still lets you judge a lot at first sight while you have to decrypt an Intel CPU number to get some useful info; it's kind of car model numbering.
June 17, 2006 12:26:04 PM

Quote:
So they say. At least on my system: XP-32 transferred a 2.5 GB folder in 2min18sec while XP-64 did it in 1min 46sec that's a pretty good difference!


a difference of 32seconds.. not bad. Hey do u happen to have a link to a benchmark test of a 32bit system VS a 64bit system in office work?
June 17, 2006 12:34:11 PM

well i have 2 hard drives one with xp64 and one with xp loaded
i found that i get 107 fps with my 1900xtx in crossfire when i run the halflife2 lostcoast in xp64
but when i do the same test with the same settings in windows xp i can only get 65fps
I am still trying to find out why but I think it is because windows xp64 manages its files and memory better
but i am haveing trouble with my drivers because there isnt the range of drivers written for windows xp64 as there is with xp
June 17, 2006 12:38:41 PM

Quote:
well i have 2 hard drives one with xp64 and one with xp loaded
i found that i get 107 fps with my 1900xtx in crossfire when i run the halflife2 lostcoast in xp64
but when i do the same test with the same settings in windows xp i can only get 65fps
I am still trying to find out why but I think it is because windows xp64 manages its files and memory better
but i am haveing trouble with my drivers because there isnt the range of drivers written for windows xp64 as there is with xp


Oh I love HL2! Is it really because of the 64bit OS or something else that is making the difference?
June 17, 2006 12:45:43 PM

Quote:
So they say. At least on my system: XP-32 transferred a 2.5 GB folder in 2min18sec while XP-64 did it in 1min 46sec that's a pretty good difference!


a difference of 32seconds.. not bad. Hey do u happen to have a link to a benchmark test of a 32bit system VS a 64bit system in office work?

Here's the paga I referred to for myself:
http://www.pcstats.com/articleview.cfm?articleid=1665&p...
June 17, 2006 1:08:59 PM

Do you play halflife2
have you got steem
if you have log onto and run halflife2 lost coast and run the video stress test with all the settings on high maxed out
i get 107 fps in 64 bit and only 65 in 32 bit
tell me there isnt a differece
June 18, 2006 9:35:56 AM

Quote:
The difference is minor right now because most people don't have a need for more than 2GB's of memory and no one here will need to access to what, 2 perabytes of memory?


True, most people don't need it. However, we're not just talking about the amount of RAM in your computer... this also includes your pagefile. So if you have 2GB of RAM and a 2GB pagefile, then you've maxxed out your addressable memory. If for some reason a program suddenly requires more than 4GB of memory... pfffffft.
June 18, 2006 1:31:08 PM

Quote:
The difference is minor right now because most people don't have a need for more than 2GB's of memory and no one here will need to access to what, 2 perabytes of memory?


True, most people don't need it. However, we're not just talking about the amount of RAM in your computer... this also includes your pagefile. So if you have 2GB of RAM and a 2GB pagefile, then you've maxxed out your addressable memory. If for some reason a program suddenly requires more than 4GB of memory... pfffffft.

That's true: It's headaches when I work with large images (7mx3m, 72dpi) etc on my 2GHz of RAM at work. When the pagefile is full it may take 10 -20 sec to apply a brush in photoshop or even halt at all. Smaller swap space means also worse physical RAM management.
a c 99 à CPUs
June 18, 2006 2:11:44 PM

--Dupe post--
June 18, 2006 2:14:55 PM

besides improvement in Graphic intensive designing and game developing are there improvements in gameplay for 64bit?
a c 99 à CPUs
June 18, 2006 2:19:07 PM

Linux and Windows are totally separate cases when it comes to 32- and 64-bit desktop versions. There have been (non-x86) versions of Linux since about 1994 (MIPS64, UltraSparc, then later Alpha, Itanic, and PPC64) and there is a 64-bit XP that was released in 2001 with the regular i386 version of XP that runs on the Itanic. There have been x86_64 Linux versions ever since AMD made the arch spec, so there have been x86_64 Linux versions since late 2003. Microsoft tried to make an x86_64 version with Windows XP x84, but that was really a proof-of-concept OS that essentially was a testbed for Vista 64-bit as Win 3.11s was a testbed for Windows 95's Win32 codebase.

Also, >99% of Linux drivers are F/OSS software and ship in the kernel sources. So if you have the source for a 32-bit driver, you can more or less just recompile for 64-bit. If you need to change some things for 64-bit, you have the source and can do that. Same for the applications. Windows largely depends on 3rd-party proprietary applications and drivers, and the availability of those solely depends on the vendors' willingness to make a new version of their driver and/or application for 64 bits.

Now as to the advantages or disadvantages of 64 bit computers- we see a little increase in the performance of the 64-bit machines mostly because the lowest common compiler optimization denominator* has been raised from generally a Pentium MMX computer (i586 + mmx) for 32 bit to the AMD64 spec (SSE, SSE2, and a few other things.) If you bother to recode your entire application to take advantage of the longer ints, floats, and doubles, you can get a significant performance boost. Also, if you are a developer, having those larger values can make your job easier if you do a new 64-bit app from scratch. But usually the 32-bit code is just recompiled, so you get little improvement outside the use of the newer SSE instructions. This recompilation leads to 64-bit apps taking up almost twice the RAM and disk space for the binaries and libraries. Perhaps the most important thing to come about with the 64-bit CPUs and OSes is the ability to address 4GB of memory well and then be able to allocate more than the 32-bit OS limit of 2GB RAM (3GB with certain kernel split options) to one running process. Windows also has been known to act funky with 4GB RAM as the PCI bus takes up an entire GB of addressing space and Windows must contend with that. Since most motherboards today support 4 or 8GB RAM and new computers commonly coming with 2GB RAM, we'll see the 32-bit wall get hit soon.

Oh, and also your pagefile or swap size does depend on the OS bit width too. I do a lot of heavy work (my process load hit 18.5 once!!) on my computer and 2GB RAM really isn't enough and I am a little short on the $$$ to go fill my computer to its 4GB max, so I put 4GB striped swap and 2GB regular swap on my disks, bringing the amount of total addressable "memory" to 8GB. I could not do that on a 32-bit system as it would only let me have a swap partition of apparent size of 2GB, so the 4GB striped one would be out and would reduce the performance of the swap by about half as well as not let me access more than 2GB swap at any one time. 64-bit systems' swap file sizes can be something like 16 terabytes currently. I do not know about Windows as the most RAM I have ever used in a Windows box is 1GB with a 1.5GB default pagefile size, leading to a 2.5GB "RAM" size.

*I have not tested this, but I am willing to bet that if you were to custom-compile the same OS (such as Gentoo) for both 32 and 64 bits with the same compiler optimizations, you will get pretty much the same speed.
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