Real bus speeds of Via 266 chipset and DDR

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

I'm posting to get some advice about REAL bus speeds.

I want to know how much my chipset and processor would benefit from
different memory. The trouble is that I have become confused by
"effective bus speed" and "actual bus speed" and "nominal bus speed"
and so on.

As you may be tired of hearing (!) I am running a Duron Applebred
1800 in a Via 266 mobo made by Syntax with 768 KB of 133 SD-RAM. The
BIOS is by Phoenix. The CPU temp under load is ok at 44 degrees C.

The manual for the mobo is available at http://tinyurl.com/9rc5d
(OR http://64.168.125.230/support/SyntaxDownloads/download_manuals/
manual_sv266a.pdf)

My Syntax mobo can run either SD-RAM or DDR. I am thinking that I
could upgrade the 768MB of 133 SD-RAM to DDR in order to get an
increase in performnce.

Then later on this year, I can build a faster PC using all new parts
except for the DDR which I could take from the existing Snytax mobo.
(I would put the slower SD-RAM back into the Syntax mobo to create a
basic PC.) I do not want to spend more money than I have to as I am
on a budget.

QUESTION ONE. What speed DIMM memory would work well with my
Via266/Duron1800 and yet still be good to use with a faster processor
later this year which will probably be a mid-power socket 939 (and
some mobo chipset which I haven't decided on yet)? Is PC2700 too
slow?

QUESTION TWO. How fast does the bus on my mobo/cpu actually run
these devices at:

(a) the "133/266 MHz FSB" on the cpu
(b) the bus on 133 MHz SD-RAM
(c) suitable DDR in Q.1 (PC2700 ??)
(d) the PCI bus.

Thank you guys.
17 answers Last reply
More about real speeds chipset
  1. Archived from groups: alt.comp.hardware.overclocking.amd,uk.comp.homebuilt,alt.comp.hardware (More info?)

    Jon D wrote:
    >
    > QUESTION ONE. What speed DIMM memory would work well with my
    > Via266/Duron1800 and yet still be good to use with a faster processor
    > later this year which will probably be a mid-power socket 939 (and
    > some mobo chipset which I haven't decided on yet)? Is PC2700 too
    > slow?

    PC2100 memory will run at 266 Mhz, but if you plan on using it in a newer system you should get at least pc2700, preferably faster.

    > QUESTION TWO. How fast does the bus on my mobo/cpu actually run
    > these devices at:
    >
    > (a) the "133/266 MHz FSB" on the cpu
    > (b) the bus on 133 MHz SD-RAM
    > (c) suitable DDR in Q.1 (PC2700 ??)
    > (d) the PCI bus.

    The FSB and memory bus run at 133 Mhz. With DDR the effective speed is double because there are two data transfers per clock cycle.
    PC2700 memory will run at up to 333 Mhz. It will also work with your slower bus.
    A standard PCI bus runs at 33 Mhz.

    --
    Mike Walsh
    West Palm Beach, Florida, U.S.A.
  2. Archived from groups: alt.comp.hardware.overclocking.amd,uk.comp.homebuilt,alt.comp.hardware (More info?)

    "Jon D" <jon_d@nomail.com> wrote in message
    news:96A088E4F58A971E5D@66.250.146.159...
    > I'm posting to get some advice about REAL bus speeds.
    >
    > I want to know how much my chipset and processor would benefit from
    > different memory. The trouble is that I have become confused by
    > "effective bus speed" and "actual bus speed" and "nominal bus speed"
    > and so on.

    I don't know what you mean by "nominal" bus speed, but "actual" and
    "effective" are quite straightforward. The "actual" bus speed is simply the
    frequency of the bus clock signal, and the "effective" bus speed is that
    frequency multiplied by the (peak) number of data transfers per clock cycle.
    The logic here is that since a traditional bus can make only one transfer
    per clock cycle, a bus that can make two transfers per clock cycle (that is,
    a Double Data Rate or DDR bus) has the same peak transfer rate as a
    traditional bus operating at twice the frequency.

    > As you may be tired of hearing (!) I am running a Duron Applebred
    > 1800 in a Via 266 mobo made by Syntax with 768 KB of 133 SD-RAM. The
    > BIOS is by Phoenix. The CPU temp under load is ok at 44 degrees C.
    [snip]
    > My Syntax mobo can run either SD-RAM or DDR. I am thinking that I
    > could upgrade the 768MB of 133 SD-RAM to DDR in order to get an
    > increase in performnce.

    I think the increase will be modest (perhaps up to 10% - not normally
    noticeable), but I don't have any figures to hand.

    > Then later on this year, I can build a faster PC using all new parts
    > except for the DDR which I could take from the existing Snytax mobo.
    > (I would put the slower SD-RAM back into the Syntax mobo to create a
    > basic PC.) I do not want to spend more money than I have to as I am
    > on a budget.
    >
    > QUESTION ONE. What speed DIMM memory would work well with my
    > Via266/Duron1800 and yet still be good to use with a faster processor
    > later this year which will probably be a mid-power socket 939 (and
    > some mobo chipset which I haven't decided on yet)? Is PC2700 too
    > slow?

    PC2700 may be usable but if so will limit performance on faster processors;
    it would be better to go for PC3200.

    > QUESTION TWO. How fast does the bus on my mobo/cpu actually run
    > these devices at:
    >
    > (a) the "133/266 MHz FSB" on the cpu
    > (b) the bus on 133 MHz SD-RAM
    > (c) suitable DDR in Q.1 (PC2700 ??)
    > (d) the PCI bus.

    I'm not sure what you are asking here. The FSB, memory bus and PCI bus are
    all separate. Usually the clock signals for each are derived (via
    dividers/multipliers) from a common source, so it's not strictly true to say
    they are independent.

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

    >> QUESTION ONE. What speed DIMM memory would work well with my
    >> Via266/Duron1800 and yet still be good to use with a faster processor
    >> later this year which will probably be a mid-power socket 939 (and
    >> some mobo chipset which I haven't decided on yet)? Is PC2700 too
    >> slow?
    >
    > PC2700 may be usable but if so will limit performance on faster
    > processors;
    > it would be better to go for PC3200.

    Simply for explanation purposes I would add that PC2700 is another name for
    DDR333 and PC3200 is another name for DDR400.
    DDR stands for Double Data Rate, so does 2 transfers per clock tick so...
    DDR333 is guaranteed to be stable on bus frequencies up to 166.666MHz and
    DDR400 can run on buses up to 200MHz. DDR400 memory (200MHz) can be used at
    slower frequencies - the rating is its maximum stable speed.
  4. Archived from groups: alt.comp.hardware.overclocking.amd,uk.comp.homebuilt,alt.comp.hardware (More info?)

    > Simply for explanation purposes I would add that PC2700 is another name
    for
    > DDR333 and PC3200 is another name for DDR400.
    > DDR stands for Double Data Rate, so does 2 transfers per clock tick so...
    > DDR333 is guaranteed to be stable on bus frequencies up to 166.666MHz and
    > DDR400 can run on buses up to 200MHz. DDR400 memory (200MHz) can be used
    at
    > slower frequencies - the rating is its maximum stable speed.
    >

    You might also want to mention that if you use DDR400 with rating of CAS3,
    the memory will run at lower CAS when using it at DDR333 or lower. For
    instance, I have DDR400 CAS3 and is running at DDR333 CAS2.5. I'm not sure
    that this is true for all brands of memory so, the BIOS should be set to
    speed detect...to make sure you don't experience any problems.
  5. Archived from groups: alt.comp.hardware.overclocking.amd,uk.comp.homebuilt,alt.comp.hardware (More info?)

    Jon D wrote:

    " QUESTION ONE. What speed DIMM memory would work well with my
    Via266/Duron1800 and yet still be good to use with a faster processor
    later this year which will probably be a mid-power socket 939 (and some
    mobo chipset which I haven't decided on yet)? Is PC2700 too slow? "

    You need PC3200 for any socket 939 CPU.


    " QUESTION TWO. How fast does the bus on my mobo/cpu actually run
    these devices at:
    (a) the "133/266 MHz FSB" on the cpu
    (b) the bus on 133 MHz SD-RAM
    (c) suitable DDR in Q.1 (PC2700 ??)
    (d) the PCI bus. "

    These two articles explain all the relevant frequencies:
    http://www.tweakfactor.com/articles/tweaks/neoocguide/3.html
    http://arstechnica.com/paedia/r/ram_guide/ram_guide.part3-1.html

    The FSB of your CPU, chipset and SDRAM is 133.33r MHz. PC2100 DDR SDRAM
    has the same bus rate as PC133 SDRAM, but is called DDR266 because it
    can transfer data on both the rising and falling edge of the clock
    cycle. It doesn't actually double the effective bus rate of 133.33r
    MHz, and the claims of it operating at 266.66r MHz are arguably just
    marketing speak.

    The PCI and AGP bus work on dividers of the motherboard chipset bus.
    When operating a chipset bus of 133.33r MHz, your PCI bus will work on a
    divider of 1/4, equalling 33.33r MHz. Your chipset bus can also operate
    at 100 MHz with slower processors, from which the PCI bus will operate
    on a divider of 1/3, also equalling 33.33r MHz. Your motherboard's AGP
    bus can operate at AGP4x, four times the speed of the PCI bus, thus
    equalling the chipset bus of 133.33r MHz.
  6. Archived from groups: alt.comp.hardware.overclocking.amd,uk.comp.homebuilt,alt.comp.hardware (More info?)

    On Wed, 27 Jul 2005 13:27:26 +0100, Jon D <jon_d@nomail.com>
    wrote:

    >I'm posting to get some advice about REAL bus speeds.
    >
    >I want to know how much my chipset and processor would benefit from
    >different memory.

    Almost none except in less common apps that have very high
    memory bandwidth needs. In such cases it might be upwards
    of 20% or so but usually under 5%.


    >The trouble is that I have become confused by
    >"effective bus speed" and "actual bus speed" and "nominal bus speed"
    >and so on.
    >

    Then just ignore ALL of those terms, as none are technically
    based and all just nonsense.

    For any bus you have 3 parameters:

    Clock generator derived frequency.
    Bus Multiplier (multiplies the clock)
    Data rate

    So for an example, given a Duron 1.8GHz you'd have a FSB
    with 133MHz clock generator, 2x bus multiplier (hence the
    term "DDR", Double Data Rate), and a data rate of (in this
    case) 2 X 133 = DDR266. It should not be called 266MHz
    because the whole purpose of the "DDR" term is to
    distinguish between clock generator rate and data rate.


    >As you may be tired of hearing (!) I am running a Duron Applebred
    >1800 in a Via 266 mobo made by Syntax with 768 KB of 133 SD-RAM. The
    >BIOS is by Phoenix. The CPU temp under load is ok at 44 degrees C.
    >
    >The manual for the mobo is available at http://tinyurl.com/9rc5d
    >(OR http://64.168.125.230/support/SyntaxDownloads/download_manuals/
    >manual_sv266a.pdf)
    >
    >My Syntax mobo can run either SD-RAM or DDR. I am thinking that I
    >could upgrade the 768MB of 133 SD-RAM to DDR in order to get an
    >increase in performnce.

    Not worthwhile.
    Youi'd get more gain by buying an nForce2 motherboard and
    slightly overclocking (or even NOT overclocking), but then
    you still need the DDR memory. KT266 chipset is simply
    slower per the same data rate, clock speeds, etc, than
    nForce2. This is ignoring the difference the memory makes
    BUT when considering the benefit of the memory one must also
    look at the rest of the bottlenecks, particularly when the
    memory isn't such a large difference.

    Howver, the biggest performance boost from a singular
    purchase would be the CPU. Again your board is a limitation
    since it only has DDR266 FSB support.


    >
    >Then later on this year, I can build a faster PC using all new parts
    >except for the DDR which I could take from the existing Snytax mobo.
    >(I would put the slower SD-RAM back into the Syntax mobo to create a
    >basic PC.) I do not want to spend more money than I have to as I am
    >on a budget.

    Frankly, there's no point in upgrading that system at all
    then. You'd be better off waiting till you had the new
    motherboard/etc so you can be sure the memory works properly
    with it. I don't mean to be offensive but rather factual
    when I note that- The parts are low-end stuff, as always
    it's expected that it'll be more problematic and expensive
    to upgrade them.


    >
    >QUESTION ONE. What speed DIMM memory would work well with my
    >Via266/Duron1800 and yet still be good to use with a faster processor
    >later this year which will probably be a mid-power socket 939 (and
    >some mobo chipset which I haven't decided on yet)? Is PC2700 too
    >slow?

    Yes, PC3200 CAS2.5 at a minimum.


    >
    >QUESTION TWO. How fast does the bus on my mobo/cpu actually run
    >these devices at:
    >
    >(a) the "133/266 MHz FSB" on the cpu

    133MHz clock, DDR266


    >(b) the bus on 133 MHz SD-RAM

    133MHz clock, Single Data Rate 133 ( 1 X, not 2 X)

    >(c) suitable DDR in Q.1 (PC2700 ??)

    133 clock, Double Data Rate

    The thing is, often memory isn't a major bottleneck, not as
    much as CPU, hard drive, video card, all depending on the
    application.

    >(d) the PCI bus.

    33MHz. That is standard and has little to do with what
    board you choose unless you try to overclock.

    >
    >Thank you guys.


    Frankly you should just put the money aside and upgrade
    everything at once, a little sooner if you're really itching
    for more performance. For many uses you might not even be
    able to perceive a difference with the DDR instead of SDR
    memory. System might feel a tiny bit snappier but it should
    easily be fast enough at typical tasks already, with the
    more demanding tasks benefitting more from a faster CPU (and
    one with more L2 cache).
  7. Archived from groups: alt.comp.hardware.overclocking.amd,uk.comp.homebuilt,alt.comp.hardware (More info?)

    On Wed, 27 Jul 2005 13:27:26 +0100, Jon D wrote:

    > I'm posting to get some advice about REAL bus speeds.
    >
    See the Real Front Side Bus in link in sig line.

    > I want to know how much my chipset and processor would benefit from
    > different memory. The trouble is that I have become confused by
    > "effective bus speed" and "actual bus speed" and "nominal bus speed"
    > and so on.
    >
    Most normal people are.:-)

    > As you may be tired of hearing (!) I am running a Duron Applebred
    > 1800 in a Via 266 mobo made by Syntax with 768 KB of 133 SD-RAM. The
    > BIOS is by Phoenix. The CPU temp under load is ok at 44 degrees C.
    >
    > The manual for the mobo is available at http://tinyurl.com/9rc5d
    > (OR http://64.168.125.230/support/SyntaxDownloads/download_manuals/
    > manual_sv266a.pdf)
    >
    > My Syntax mobo can run either SD-RAM or DDR. I am thinking that I
    > could upgrade the 768MB of 133 SD-RAM to DDR in order to get an
    > increase in performnce.
    >
    > Then later on this year, I can build a faster PC using all new parts
    > except for the DDR which I could take from the existing Snytax mobo.
    > (I would put the slower SD-RAM back into the Syntax mobo to create a
    > basic PC.) I do not want to spend more money than I have to as I am
    > on a budget.
    >
    > QUESTION ONE. What speed DIMM memory would work well with my
    > Via266/Duron1800 and yet still be good to use with a faster processor
    > later this year which will probably be a mid-power socket 939 (and
    > some mobo chipset which I haven't decided on yet)? Is PC2700 too
    > slow?
    >
    If buying today, you should buy the fastest reasonably priced ram. I'd say
    that's PC3200 which is rated for a 200MHz bus (DDR400). However, you can
    use ram as slow as PC2100 (133MHz DDR266) in both your current board and
    most/some A64 boards. Buying the ram today won't help your current system
    much at all. Your delima is what will ram prices be later on when you
    actually need the DDR ram. Ram is cheap now, but will it be cheaper later????

    > QUESTION TWO. How fast does the bus on my mobo/cpu actually run
    > these devices at:
    >
    > (a) the "133/266 MHz FSB" on the cpu

    133MHz clock. DDR266.

    > (b) the bus on 133 MHz SD-RAM

    133MHz clock

    > (c) suitable DDR in Q.1 (PC2700 ??)

    133MHz clock DDR266, but don't think that will improve performance by a
    big margin. It won't. Approximately 90% of CPU data request are serviced
    by the CPU cache and the speed of the external ram has very little to do
    with it. At most I would guess you'd get a 5% overall performance increase
    over standard sdram. You also need to remember that the ram controller is
    in the chipset and all the ram data must share the FSB path to the CPU,
    which is DDR even with SDR ram.

    > (d) the PCI bus.
    >
    It should be 33MHz on any board, but it will go higher if you overclock
    the FSB and your MB doesn't have a PCI lock. And yours doesn't.

    --
    KT133 MB, CPU @2400MHz (24x100): SIS755 MB CPU @2330MHz (10x233)
    Need good help? Provide all system info with question.
    My server http://wesnewell.no-ip.com/cpu.php
    Verizon server http://mysite.verizon.net/res0exft/cpu.htm
  8. Archived from groups: alt.comp.hardware.overclocking.amd,uk.comp.homebuilt,alt.comp.hardware (More info?)

    On Wed, 27 Jul 2005 14:55:22 +0100, Cuzman wrote:

    > Jon D wrote:
    >
    > " QUESTION ONE. What speed DIMM memory would work well with my
    > Via266/Duron1800 and yet still be good to use with a faster processor
    > later this year which will probably be a mid-power socket 939 (and some
    > mobo chipset which I haven't decided on yet)? Is PC2700 too slow? "
    >
    > You need PC3200 for any socket 939 CPU.
    >
    While PC3200 or faster would be preferred, it's certainly not a
    requirement. The system will run fine on PC2700. I'm not sure what the
    bottom limit is but PC2100 should also work, maybe. It will in my 754
    system. From the AMD product brief...

    An integrated memory controller with peak memory bandwidth of up to 6.4
    GB/sec, supporting PC3200, PC2700, PC2100, or PC1600 DDR SDRAM

    --
    KT133 MB, CPU @2400MHz (24x100): SIS755 MB CPU @2330MHz (10x233)
    Need good help? Provide all system info with question.
    My server http://wesnewell.no-ip.com/cpu.php
    Verizon server http://mysite.verizon.net/res0exft/cpu.htm
  9. Archived from groups: alt.comp.hardware.overclocking.amd,uk.comp.homebuilt,alt.comp.hardware (More info?)

    On Wed, 27 Jul 2005 11:48:36 -0400, Mike Walsh wrote:

    > Jon D wrote:
    >>
    >> QUESTION ONE. What speed DIMM memory would work well with my
    >> Via266/Duron1800 and yet still be good to use with a faster processor
    >> later this year which will probably be a mid-power socket 939 (and some
    >> mobo chipset which I haven't decided on yet)? Is PC2700 too slow?
    >
    > PC2100 memory will run at 266 Mhz, but if you plan on using it in a
    > newer system you should get at least pc2700, preferably faster.
    >
    Nope. It's actual bus clock is 133MHz (DDR266), but not 266MHz.

    --
    KT133 MB, CPU @2400MHz (24x100): SIS755 MB CPU @2330MHz (10x233)
    Need good help? Provide all system info with question.
    My server http://wesnewell.no-ip.com/cpu.php
    Verizon server http://mysite.verizon.net/res0exft/cpu.htm
  10. Archived from groups: alt.comp.hardware.overclocking.amd,uk.comp.homebuilt,alt.comp.hardware (More info?)

    "Jon D" <jon_d@nomail.com> wrote in message
    news:96A088E4F58A971E5D@66.250.146.159...
    > I'm posting to get some advice about REAL bus speeds.
    >
    > I want to know how much my chipset and processor would benefit from
    > different memory. The trouble is that I have become confused by
    > "effective bus speed" and "actual bus speed" and "nominal bus speed"
    > and so on.

    I have the same board and the bus speed is 133mhz. Some sockets on the
    board run on a locked ratio of that bus speed - for example the PCI slots
    run at 33mhz or 1/4 and memory runs at 133mhz like your SDRAM does.
    Some components on that board can run at 266mhz such as the CPU
    which runs internally at double the bus speed and DDR if you install it
    will run at double the bus speed.

    If you put in PC3200/DDR400 it will only run at the stock speed of 133mhz
    (x2 is 266mhz which is the speed of PC2100/DDR266) but you could
    overclock the FSB a little if you put in that RAM - you do it in the Bios
    and if you put it up to say 140mhz your CPU would perform like a 1900
    or 2000. Every component connected to that board would run a little faster
    and of course a little hotter so make sure your case has decent cooling if
    you
    do that.

    Your overclocking potential is limited on that board because you can only
    raise the CPU core
    voltage by up to .75v - a real overclockers board would allow about 3x that
    adjustment.

    I went from SDRAM to DDR on this board and it made a noticeable differance -
    I never benchmarked
    it but most ppl say the differance is 10% - it just felt quicker. Going from
    512mb to 1gb made the biggest
    differance - playing any modern game (HL2, Doom3, Far Cry etc on WinXP) with
    less than 1gb and you
    are bound to get plenty of Hard Disk access and stuttering. But playing
    those games on a Duron 1800 isnt
    that great either. But Im not sure you have a Duron - theres no such chip as
    an Applebred - if you mean
    Thoroughbred then thats a Athlon XP1800 you have. Use this program to check
    http://www.cpuid.org/cpuz.php - it'll also diagnose your RAM and tell you
    its CAS speed.

    I have a XP2400 (the fastest CPU that board can support) with 1gb DDR
    running at the stock 133mhz
    like PC2100 even though its PC2700 and a Radeon 9700. I can play HL2 at
    1024x768 High settings
    and its smooth. Doom 3 I use 800x600 medium settings and Far Cry 1024
    med/high settings works great.
    I never worry about resolutions higher than 1024 since I use an old CRT
    monitor - a Sony Trinitron tube
    with flat screen that looks just fine.

    When I had just 512mb of RAM I was getting plenty of Hard Disk access during
    games that causes that
    stuttering effect and a cheap option that helped a lot was putting an old
    Hard Drive back in my system.
    I had a 120gb new drive with everything on including the pagefile. I put the
    old drive in as a slave drive
    or D - formatted it - and put the pagefile on that instead of the C drive -
    at a fixed size of 2gb.
    That way when my RAM was used up and virtual RAM was being used there were 2
    drive heads handling
    the movement of data instead of just one and that reduced the stuttering
    effect noticeably. Maybe this is an option
    you can consider?

    Hope this helps.

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

    On Thu 28 Jul 2005 09:03:51, Sleepy wrote:
    >
    > But Im not sure you have a Duron - theres no such chip as
    > an Applebred -

    Definitely an Applebred. See

    http://www.madshrimps.be/printart.php?articID=106

    "The Applebred is the new revision of the Duron series from AMD. It
    is a tuned down Thoroughbred B CPU"
  12. Archived from groups: alt.comp.hardware.overclocking.amd,uk.comp.homebuilt,alt.comp.hardware (More info?)

    On Thu, 28 Jul 2005 21:23:24 +0100, Jon D wrote:

    > On Thu 28 Jul 2005 09:03:51, Sleepy wrote:
    >>
    >> But Im not sure you have a Duron - theres no such chip as
    >> an Applebred -
    >
    > Definitely an Applebred. See
    >
    > http://www.madshrimps.be/printart.php?articID=106
    >
    > "The Applebred is the new revision of the Duron series from AMD. It
    > is a tuned down Thoroughbred B CPU"

    Hogwash. It's just a Tbred A or B core with the cache size set for 64k.
    Reference AMD doc Processor Model 8 Data Sheet, 25848.pdf

    Calling it Applebred or wheat bread won't change those facts. New cores
    ALWAYS have new CPUID's. Now what I heard was that the Applebred was a
    Barton core with only 64K cache enabled. So take your pick. In any case,
    it is not a new core, just a new nickname, and if you get an older Tbred A
    core, you won't be able to overclock it much either.

    --
    KT133 MB, CPU @2400MHz (24x100): SIS755 MB CPU @2330MHz (10x233)
    Need good help? Provide all system info with question.
    My server http://wesnewell.no-ip.com/cpu.php
    Verizon server http://mysite.verizon.net/res0exft/cpu.htm
  13. Archived from groups: alt.comp.hardware.overclocking.amd,uk.comp.homebuilt,alt.comp.hardware (More info?)

    On Wed 27 Jul 2005 14:55:22, Cuzman wrote:
    <news:dc83o9$uav$1@news.freedom2surf.net>

    > Jon D wrote:
    >
    > " QUESTION ONE. What speed DIMM memory would work well with my
    > Via266/Duron1800 and yet still be good to use with a faster
    > processor later this year which will probably be a mid-power
    > socket 939 (and some mobo chipset which I haven't decided on
    > yet)? Is PC2700 too slow? "
    >
    > You need PC3200 for any socket 939 CPU.
    >
    >
    > " QUESTION TWO. How fast does the bus on my mobo/cpu actually
    > run these devices at:
    > (a) the "133/266 MHz FSB" on the cpu
    > (b) the bus on 133 MHz SD-RAM
    > (c) suitable DDR in Q.1 (PC2700 ??)
    > (d) the PCI bus. "
    >
    > These two articles explain all the relevant frequencies:
    > http://www.tweakfactor.com/articles/tweaks/neoocguide/3.html
    > http://arstechnica.com/paedia/r/ram_guide/ram_guide.part3-1.html
    >

    Nice links. Thank you. From reading your links and also Wes
    Newell's page ("The Real FSB") I think I can see where I was just not
    getting started off on a proper understanding.

    I had seen the spec for the FSB of some AMD cpu stated in some places
    as 100 MHz (or 133 MHz or whatever) and then I had seen the specs for
    the same chip but with double the FSB value - ie 200 (or 266 or
    whatever).

    The single/lower value seems to be the actual clock speed of the FSb
    but the double/larger value is the Data Rate. And that term is
    nominal because, so it seems, in the original designation there was
    no reference by AMD to MHz. Other (later?) AMD documents seem to
    contain the term MHz, for example http://tinyurl.com/ytjqq

    I guess it's all a bit like the Athlon model numbers with the plus
    sign after them: the cpu does not run at that speed but was
    originally a guideline of the cpu's claimed speed when comparing
    Intel chips.


    > The FSB of your CPU, chipset and SDRAM is 133.33r MHz. PC2100
    > DDR SDRAM has the same bus rate as PC133 SDRAM, but is called
    > DDR266 because it can transfer data on both the rising and
    > falling edge of the clock cycle. It doesn't actually double the
    > effective bus rate of 133.33r MHz, and the claims of it
    > operating at 266.66r MHz are arguably just marketing speak.

    What you say is almost the same as I just wrote exept that the AMD
    document I link to above claims the Duron's FSB is the higher/double
    rate but that is pretty misleading if SD-RAM is used which IIRC is
    all that was available for the early Duron.


    > The PCI and AGP bus work on dividers of the motherboard chipset
    > bus. When operating a chipset bus of 133.33r MHz, your PCI bus
    > will work on a divider of 1/4, equalling 33.33r MHz. Your
    > chipset bus can also operate at 100 MHz with slower processors,
    > from which the PCI bus will operate on a divider of 1/3, also
    > equalling 33.33r MHz. Your motherboard's AGP bus can operate at
    > AGP4x, four times the speed of the PCI bus, thus equalling the
    > chipset bus of 133.33r MHz.

    Useful. Thanks.
  14. Archived from groups: alt.comp.hardware.overclocking.amd,uk.comp.homebuilt,alt.comp.hardware (More info?)

    -- trimmed --

    On Wed 27 Jul 2005 21:21:36, Wes Newell wrote:
    <news:pan.2005.07.27.20.23.18.275753@TAKEOUTverizon.net>

    > On Wed, 27 Jul 2005 13:27:26 +0100, Jon D wrote:
    >
    >> I'm posting to get some advice about REAL bus speeds.
    >>
    > See the Real Front Side Bus in link in sig line.

    Good article of yours. Thank you!


    -- snip --


    >> QUESTION ONE. What speed DIMM memory would work well with my
    >> Via266/Duron1800 and yet still be good to use with a faster
    >> processor later this year which will probably be a mid-power
    >> socket 939 (and some mobo chipset which I haven't decided on
    >> yet)? Is PC2700 too slow?
    >>
    > If buying today, you should buy the fastest reasonably priced
    > ram. I'd say that's PC3200 which is rated for a 200MHz bus
    > (DDR400). However, you can use ram as slow as PC2100 (133MHz
    > DDR266) in both your current board and most/some A64 boards.
    > Buying the ram today won't help your current system much at all.
    > Your delima is what will ram prices be later on when you
    > actually need the DDR ram. Ram is cheap now, but will it be
    > cheaper later????
    >
    >> QUESTION TWO. How fast does the bus on my mobo/cpu actually
    >> run these devices at:
    >>
    >> (a) the "133/266 MHz FSB" on the cpu
    >
    > 133MHz clock. DDR266.
    >
    >> (b) the bus on 133 MHz SD-RAM
    >
    > 133MHz clock
    >
    >> (c) suitable DDR in Q.1 (PC2700 ??)
    >
    > 133MHz clock DDR266, but don't think that will improve
    > performance by a big margin. It won't. Approximately 90% of CPU
    > data request are serviced by the CPU cache and the speed of the
    > external ram has very little to do with it. At most I would
    > guess you'd get a 5% overall performance increase over standard
    > sdram. You also need to remember that the ram controller is in
    > the chipset and all the ram data must share the FSB path to the
    > CPU, which is DDR even with SDR ram.
    >
    >> (d) the PCI bus.
    >>
    > It should be 33MHz on any board, but it will go higher if you
    > overclock the FSB and your MB doesn't have a PCI lock. And yours
    > doesn't.


    Wes. how do you know my mobo doesn't have a PCI lock? :-) Are
    you referring to the BIOS setting "Auto Detect DIMM/PCI Clk"?

    So how do I use this setting to my advantage?

    Do I need to disable the auto detect in that setting (i.e. say no
    to that setting) and then vary the "CPU Host Clock" value?

    I am sure I have got noticeable improvements from varying the "CPU
    Host Clock" value but leave the DIMM/PCI Clock setting on AUTO.
    Could this have been possible?
  15. Archived from groups: alt.comp.hardware.overclocking.amd,uk.comp.homebuilt,alt.comp.hardware (More info?)

    On Thu 28 Jul 2005 09:03:51, Sleepy wrote:
    <news:Hj0Ge.42617$Pf3.38450@fe2.news.blueyonder.co.uk>
    >
    >
    > If you put in PC3200/DDR400 it will only run at the stock speed
    > of 133mhz (x2 is 266mhz which is the speed of PC2100/DDR266) but
    > you could overclock the FSB a little if you put in that RAM -
    > you do it in the Bios and if you put it up to say 140mhz your
    > CPU would perform like a 1900 or 2000. Every component connected
    > to that board would run a little faster and of course a little
    > hotter so make sure your case has decent cooling if you
    > do that.
    >
    > Your overclocking potential is limited on that board because you
    > can only raise the CPU core
    > voltage by up to .75v - a real overclockers board would allow
    > about 3x that adjustment.
    >
    > I went from SDRAM to DDR on this board and it made a noticeable
    > differance - I never benchmarked
    > it but most ppl say the differance is 10% - it just felt
    > quicker. Going from 512mb to 1gb made the biggest
    > differance - playing any modern game (HL2, Doom3, Far Cry etc on
    > WinXP) with less than 1gb and you
    > are bound to get plenty of Hard Disk access and stuttering. But
    > playing those games on a Duron 1800 isnt
    > that great either. But Im not sure you have a Duron - theres no
    > such chip as an Applebred - if you mean
    > Thoroughbred then thats a Athlon XP1800 you have. Use this
    > program to check http://www.cpuid.org/cpuz.php - it'll also
    > diagnose your RAM and tell you its CAS speed.
    >
    > I have a XP2400 (the fastest CPU that board can support) with
    > 1gb DDR running at the stock 133mhz
    > like PC2100 even though its PC2700 and a Radeon 9700. I can play
    > HL2 at 1024x768 High settings
    > and its smooth. Doom 3 I use 800x600 medium settings and Far Cry
    > 1024 med/high settings works great.
    > I never worry about resolutions higher than 1024 since I use an
    > old CRT monitor - a Sony Trinitron tube
    > with flat screen that looks just fine.
    >
    > When I had just 512mb of RAM I was getting plenty of Hard Disk
    > access during games that causes that
    > stuttering effect and a cheap option that helped a lot was
    > putting an old Hard Drive back in my system.
    > I had a 120gb new drive with everything on including the
    > pagefile. I put the old drive in as a slave drive
    > or D - formatted it - and put the pagefile on that instead of
    > the C drive - at a fixed size of 2gb.
    > That way when my RAM was used up and virtual RAM was being used
    > there were 2 drive heads handling
    > the movement of data instead of just one and that reduced the
    > stuttering effect noticeably. Maybe this is an option
    > you can consider?
    >
    > Hope this helps.
    >
    > Ben


    Ben/Sleepy, thank you very much for helping me further with this.
    You make some valuable points. The thing I am not so sure about is
    the query I raised with Wes in this same thread in my message:
    <news:96A1DD23CCC4171E5D@66.250.146.159>

    Maybe you know the answer to what I ask from your own experience.
    Wes observed that I didn't have a PCI Lock and I asked:

    Are you referring to the BIOS setting "Auto Detect DIMM/PCI Clk"

    If so then how do I use that setting to my advantage?

    Do I need to disable the auto detect in that setting (i.e. say no
    to that setting) and then vary the "CPU Host Clock" value?

    I'm sure I have got noticeable improvements from varying the "CPU
    Host Clock" value but leave the DIMM/PCI Clock setting on AUTO.
    Could this have been possible?
  16. Archived from groups: alt.comp.hardware.overclocking.amd,uk.comp.homebuilt,alt.comp.hardware (More info?)

    On Thu, 28 Jul 2005 21:49:47 +0100, Jon D <jon_d@nomail.com>
    wrote:

    >Ben/Sleepy, thank you very much for helping me further with this.
    >You make some valuable points. The thing I am not so sure about is
    >the query I raised with Wes in this same thread in my message:
    ><news:96A1DD23CCC4171E5D@66.250.146.159>
    >
    >Maybe you know the answer to what I ask from your own experience.
    >Wes observed that I didn't have a PCI Lock and I asked:

    Not having a PCI lock merely means that if you choose to
    overclock by raising the FSB, the resulting PCI bus speed
    will be divided by 4. For example, if you manually set your
    board to use 155MHz FSB (if the bios even allows that), then
    the resulting PCI bus speed would be: 155/4 = 38.75MHz.
    That's usually too high a PCI bus speed and would be
    instable.


    >
    >Are you referring to the BIOS setting "Auto Detect DIMM/PCI Clk"

    No that setting has no effect on the (lack of) PCI lock.
    Instead it causes the board to read and use the memory SPD
    programmed values on your memory modules, then use
    bios-contained logic to automatically set the memory bus
    frequency and timings. It's meant to be an "automatic" way
    of setting the system parameters without the users needing
    to know how to set it themselves. The alternative to "auto"
    (automatic) setting is manually setting it. Do that if you
    know what the settings should be. It should be same speed
    as the FSB, and the correct memory timings that your memory
    is spec'd to be able to use. Then you would need to
    extensively test memory stability.

    It's really not worth changing all these settings, at most
    it would get you a very tiny performance increase, but also
    has the potential to make system slower if set incorrectly.
    Any kinds of changes made are a very minor impact on system
    performance compared to something as simply as switching
    from a Duron to Athlon CPU.


    >
    >If so then how do I use that setting to my advantage?

    Being "auto" is how you should leave it. These settings
    should not be changed unless you know they need changed,
    which you do not.

    If you were to download and run "CPU-Z", it will show you
    what your programmed memory timings are and also the
    actually-used memory timings. You can compare these to see
    if your memory is being ran at optimal timings. As far as
    oveclocking, that is a try-it-and-see scenario, you would
    have to make guesstimations about how fast the memory might
    run. It's not worth the risks on that system.


    >
    >Do I need to disable the auto detect in that setting (i.e. say no
    >to that setting) and then vary the "CPU Host Clock" value?

    You do not "need" to do anything if the system is running
    stabily. Test it with memtest86. You could try increasing
    the CPU host clock value but it seems (based on your
    question) that you need a more basic understanding of
    overclocking before making such changes. There are various
    tutorials on the 'net, Google search for some.


    >
    >I'm sure I have got noticeable improvements from varying the "CPU
    >Host Clock" value but leave the DIMM/PCI Clock setting on AUTO.
    >Could this have been possible?

    It's possible. That doesn't mean it's true. Benchmarks
    would be needed to demonstrate the effect of any settings
    changes.
  17. Archived from groups: alt.comp.hardware.overclocking.amd,uk.comp.homebuilt,alt.comp.hardware (More info?)

    "Jon D" <jon_d@nomail.com> wrote in message
    news:96A1DE10D25F671E5D@66.250.146.159...
    > On Thu 28 Jul 2005 09:03:51, Sleepy wrote:
    > <news:Hj0Ge.42617$Pf3.38450@fe2.news.blueyonder.co.uk>
    >>
    >>
    >> If you put in PC3200/DDR400 it will only run at the stock speed
    >> of 133mhz (x2 is 266mhz which is the speed of PC2100/DDR266) but
    >> you could overclock the FSB a little if you put in that RAM -
    >> you do it in the Bios and if you put it up to say 140mhz your
    >> CPU would perform like a 1900 or 2000. Every component connected
    >> to that board would run a little faster and of course a little
    >> hotter so make sure your case has decent cooling if you
    >> do that.
    >>
    >> Your overclocking potential is limited on that board because you
    >> can only raise the CPU core
    >> voltage by up to .75v - a real overclockers board would allow
    >> about 3x that adjustment.
    >>
    >> I went from SDRAM to DDR on this board and it made a noticeable
    >> differance - I never benchmarked
    >> it but most ppl say the differance is 10% - it just felt
    >> quicker. Going from 512mb to 1gb made the biggest
    >> differance - playing any modern game (HL2, Doom3, Far Cry etc on
    >> WinXP) with less than 1gb and you
    >> are bound to get plenty of Hard Disk access and stuttering. But
    >> playing those games on a Duron 1800 isnt
    >> that great either. But Im not sure you have a Duron - theres no
    >> such chip as an Applebred - if you mean
    >> Thoroughbred then thats a Athlon XP1800 you have. Use this
    >> program to check http://www.cpuid.org/cpuz.php - it'll also
    >> diagnose your RAM and tell you its CAS speed.
    >>
    >> I have a XP2400 (the fastest CPU that board can support) with
    >> 1gb DDR running at the stock 133mhz
    >> like PC2100 even though its PC2700 and a Radeon 9700. I can play
    >> HL2 at 1024x768 High settings
    >> and its smooth. Doom 3 I use 800x600 medium settings and Far Cry
    >> 1024 med/high settings works great.
    >> I never worry about resolutions higher than 1024 since I use an
    >> old CRT monitor - a Sony Trinitron tube
    >> with flat screen that looks just fine.
    >>
    >> When I had just 512mb of RAM I was getting plenty of Hard Disk
    >> access during games that causes that
    >> stuttering effect and a cheap option that helped a lot was
    >> putting an old Hard Drive back in my system.
    >> I had a 120gb new drive with everything on including the
    >> pagefile. I put the old drive in as a slave drive
    >> or D - formatted it - and put the pagefile on that instead of
    >> the C drive - at a fixed size of 2gb.
    >> That way when my RAM was used up and virtual RAM was being used
    >> there were 2 drive heads handling
    >> the movement of data instead of just one and that reduced the
    >> stuttering effect noticeably. Maybe this is an option
    >> you can consider?
    >>
    >> Hope this helps.
    >>
    >> Ben
    >
    >
    > Ben/Sleepy, thank you very much for helping me further with this.
    > You make some valuable points. The thing I am not so sure about is
    > the query I raised with Wes in this same thread in my message:
    > <news:96A1DD23CCC4171E5D@66.250.146.159>
    >
    > Maybe you know the answer to what I ask from your own experience.
    > Wes observed that I didn't have a PCI Lock and I asked:
    >
    > Are you referring to the BIOS setting "Auto Detect DIMM/PCI Clk"
    >
    > If so then how do I use that setting to my advantage?
    >
    > Do I need to disable the auto detect in that setting (i.e. say no
    > to that setting) and then vary the "CPU Host Clock" value?
    >
    > I'm sure I have got noticeable improvements from varying the "CPU
    > Host Clock" value but leave the DIMM/PCI Clock setting on AUTO.
    > Could this have been possible?

    Yep - just alter the CPU Host/ PCI Clock setting from 133mhz to 140mhz. Boot
    up and you should see the CPU noted as running faster in the initial boot up
    screen. Use that program I mentioned (CPU-Z) in Windows and it'll confirm
    the higher CPU and RAM speeds. With one of my sticks of RAM I managed 148mhz
    which made my XP2400 perform like an XP2600 (or maybe higher) but the other
    stick was unstable cause I couldnt run the TRAS setting low enough. If its
    unstable at 140mhz then raise the Core Voltage Regulator setting on the same
    Bios page. Use a temperature monitoring program like Via hardware Monitor or
    Motherboard Monitor and remember 40s are good - 50s are okay but if you hit
    60c forget it and run at normal speeds.
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