** A64 Overclocking Guide **

Discussion in 'Links' started by THunDA, May 31, 2005.

  1. THunDA

    THunDA Ancient Guru

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    **Disclaimer**
    Overclocking can possibly damage hardware if not done with care, and sometimes even when care has been taken.
    Guru3D, WildStyle or me (THunDA) will NOT be responsible for anything that might get damaged while overclocking.



    Since there seems to be a large increase of people upgrading to a64 rigs WildStyle and I (THunDA) have decided to write up a little guide to help everyone overclocking their A64 rigs. (THunDA can take full credit for this.. hehe)

    First we are gonna go over most of the basic settings that you will find in an A64 motherboard BIOS. It’s possible that different manufacturers might have things named differently, but they should be similar for the most part. If you are unsure of a setting then be sure to ask. After this we will explain how to find the max of each component separately which is the most important and overlooked part of overclocking.


    FSB/HTT Bus Frequency
    This is what most of us know as Front side bus ( FSB ) but now with a64’s it is called HyperTransport Bus Frequency ( HTT )..
    LDT/FSB Frequency Ratio
    LDT is just like your CPU multiplier but it’s the multiplier that makes up your total HTT speed. Here is something I’ll quote from Wild that shows how to get your total HTT frequency..
    **Important note**
    When overclocking you want to lower this setting to maintain stability. On a socket 754 its best to keep your total HTT speed around 1600htt or less, as Wild explains below this will not effect performance if running under spec a little.. On socket 939 its best to keep it around 2000htt.. Sometimes on 939 you can even get away with overclocking the HTT buss a little but honestly Ive never seen a performance boost by doing this..

    CPU/FSB Frequency Ratio
    This is your CPU multiplier.. This times your HTT\FSB is how you get your CPU frequency..

    **Important note**
    On all a64 systems it is not recommended to use half multipliers ( i.e. 8.5,9.5,10.5) because this will put your ram on a ratio which means it will be running slower then you think and not the same as you have your HTT\FSB set to no matter what..

    A quote here from Wild shows what happens to your ram speed when using half multis…

    CPU VID StartUp Value
    This is the voltage that is applied to your cpu before the Vid and special are applied during post.. I havent found this to be a very important setting but normally I just leave it at 1.5v .. I also ran this using the Startup setting and it didnt seem to effect anything in a bad or good way.. So from my personal experience its not really a vital setting..

    CPU VID Control
    This is your vcore which is your CPU’s voltage setting ..

    CPU VID Special Control
    This may be named different depending on the motherboard but it normally has options that look like this..

    104%, 110%, 113%, 123%, 126%, 133%, 136%

    What this does is let you add more vcore to your CPU when your regular vcore options are not enough.. What you do is multiply your CPU VID Control with your CPU VID Special Control to get your actual vcore. Here is an example of using the VID Special..

    CPU VID Control = 1.50
    CPU VID Special = 110%

    1.50 x 110% = 1.65v
    So with this setting your giving your CPU 1.65 vcore.

    And for you lazy people check this out..
    This says its for the DFI 250gb mobo but it will work for any mobo that lets you add % to the vcore..

    [​IMG]

    Chipset Voltage Control
    This is the voltage applied to your motherboard chipset. The stock voltage for my chipset is 1.5v, but currently I’m running mine at 1.7v just to make sure its getting enough juice since it runs pretty cool for me anyway. I haven’t noticed much of an improvement in stability with upping this voltage as I did when I had a nforce2 motherboard but I like to up it a little anyways.
     
    Last edited by a moderator: Dec 6, 2005
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  2. THunDA

    THunDA Ancient Guru

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    AGP Voltage Control
    This is the voltage applied to your AGP slot... Sometimes upping this will help a little with stability in 3d benchmarks or games when you’re overclocking a lot. Some of you with PCI-E boards like my self will not see this as an option in bios.

    AGP Frequency\ PCI-E Frequency
    This is the bus frequency of your AGP\PCI-E slot. You wanna treat this very much like AGP voltage because it doesn’t really help a lot with stability, but sometimes it may help a little to bump it up a FEW MHz.

    Dram Voltage Control or Vdimm
    This is your RAM voltage. Setting this will vary a lot depending on what type of ram you use and more importantly what IC’s are on your ram sticks. Some ram will like a lot and then there is some ram that will be less stable with too much.

    For more info on RAM, check this thread out:
    http://forums.guru3d.com/showthread.php?s=&threadid=95128

    K8 Cool 'n' Quiet Support
    This option, when enabled automatically lowers your vcore and CPU multiplier when the system is idle. It’s highly recommended to disable this setting when overclocking.

    FSB Frequency Ratio

    This is your Dram ratio option. This is another one that might be listed different depending on what board you have. The options might look something like this though…

    100(Mhz)(1/02), 120(Mhz)(3/05), 133(Mhz)(2/03), 140(Mhz)(7/10), 150(Mhz)(3/04), 166(Mhz)(5/06), 180(Mhz)(9/10), 200(Mhz)(1/01).

    When this option is set to 200(1/01) it means your ram is running the same speed as your FSB\HTT. If you lower it then it puts your ram on a ratio which would make it run slower then your FSB\HTT setting. You might want to do this if you have poor overclocking RAM, but still want to overclock your CPU. You can still see great gains in performance from overclocking on a divider since a divider has next to no performance impact on an A64.

    Here is the way you calculate out how fast your ram is running using the 9/10 ratio and a 300HTT speed:

    300HTT / 10 * 9 = 270mhz memory speed.

    So its always...
    HTT speed divided by the second number in the ratio and then times the first number in the ratio.

    Here is one more example, this time we will use 270HTT with the 5/06 ratio.

    270HTT / 6 * 5 = 225mhz memory speed.

    Now for the lazy people I have a nice little app here that was made by goddh0r.. You can input your htt, cpu multi and divider then it will tell you what speed your ram is running at..

    A64MemFreq 1.1 by goddh0r
     
    Last edited by a moderator: Dec 14, 2005
  3. THunDA

    THunDA Ancient Guru

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    Now we are getting closer to the fun part of overclocking.. !!

    But first I’m gonna list some programs that you will NEED with links to download for testing stability. Everyone has their favorite program for testing but these are my favorites lately:

    Memtest ver. 1.51
    http://downloads.guru3d.com/download.php?det=996

    Prime95 ver. 24.11
    http://www.mersenne.org/gimps/p95v2411.zip

    SuperPi
    http://superpi.radeonx.com/

    OCCT
    ftp://ftp2.ocbase.com/ocbase3/OpenBeta/OCCTv0.91.exe

    3dMark01, 3dMark03, 3dMark05
    01 = http://downloads.guru3d.com/download.php?det=320
    03 = http://downloads.guru3d.com/download.php?det=576
    05 = http://downloads.guru3d.com/download.php?det=874

    **Important note**
    You will NEED some type of temperature monitoring program to watch your temps. Most motherboards come with a utility for this or you may be able to download it from the manufacturer’s site. Sometimes these temp programs are not the most accurate and I would really recommend to check around from others that use your mobo\CPU combo and find out if they are at least close.


    Here is a link to a thread by Soundx98, with a config file for motherboard monitor that he was nice enough to make which works great with DFI NF3 and DFI NF4 mobo's..

    http://www.dfi-street.com/forum/showthread.php?t=6798

    Finding the max of your CPU\RAM

    Finding the max of each component is very important in overclocking. Many people think they can just up the HTT and be done with it, but that’s not true most of the time because then you might get instability and not know what the source is. To me, not finding the max of each component is like fighting a group of people at once when you have the option to fight them one at a time. The first thing I like to do is find the max of my CPU and then my ram.

    To find the max of your CPU you want to take out your other components as variables, so this is what I do:

    CPU/FSB Frequency Ratio (CPU Multi) to default. Do NOT use the auto setting! Manually set it to whatever your default multi is.

    LDT/FSB Frequency Ratio (LDT Multi) to 2.5x or 3x.
    Setting this lower right now will make sure that your total HTT speed doesn’t cause instability.

    LDT/FSB Frequency Ratio (Ram Ratio) to 100(Mhz)(1/02)
    This is much lower then you should ever set this but it will make sure your ram is running way under spec and wont be causing you any problems at this point..

    CPU VID (Voltage Identification) Control (CPU Vcore)
    This is a tricky one.. Its gonna depend on how good your temps are and how far your willing to take it. For 90nm cores (i.e. Sandiego, Venice, x2, Winnies) its best to stick around 1.6v-1.65v MAX, For 130nm cores (i.e. Clawhammer, newcastles) you can go a little higher to 1.7v-1.75v but always make sure temps are good. If you have extreme cooling like water or phase then you can take the voltages higher. You could also try to see how far you will get on stock vcore first or just bump it up from the start. This is totally up to you and what you feel comfortable with. Some A64 CPU’s actually overclock better with less voltage that’s why its good to start off lower to find the max of that and if your unhappy or want more then you up it from there.

    **Important Note**
    Load is when your CPU usage is at 100%. This will happen while playing games and also when running the stability testing programs I listed above, especially OCCT and Prime as they will make your CPU usage 100% for sure. Load temps for CPU’s should always stay at or below 50c, a little over 50c wont hurt either but lower is always better.. If your temps are exceeding 50c by a lot then you either need to upgrade the cooling or lower your voltages and\or clocks.
     
    Last edited by a moderator: Dec 6, 2005
  4. THunDA

    THunDA Ancient Guru

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    Ok.. now that you lowered the LDT multi, put your ram on a ratio, set your default CPU multi manually and decided what vcore you want to start with its time to start testing..

    You want to start raising your HTT\FSB in 10-15mhz increments and in between each move you want to boot into windows and run the SuperPi 32m test. It will take about 30-45 mins normally. If it passes that then keep upping the HTT until SuperPi gives an error then back it down a few MHz (1 or 2) at a time until its stable again...

    **Remember to monitor temps**

    Once you find the highest spot where SuperPi is happy you want to run the OCCT 30min test (Not the torture option.) This test is a little tougher then SuperPi and if OCCT fails then lower your HTT\FSB 1 or 2mhz until you can pass OCCT..

    **Remember to monitor temps**

    At this point you can run each 3dmark bench to see if they complete without a crash or error. Don’t worry about the scores being low, this is because we slowed everything else down except the CPU.. If they all pass then we are off to Prime time.. hehe. This is the last thing you will run to test the stability of your CPU . Many people are going to have their own amount of time they like to run prime. Personally I run it for 8-10 hours but some like to run it 24 hours before they consider their system stable. I can understand running it for 24 hours when you’re comparing between peoples stable clocks to make sure they are all stable with the same guide lines but I never felt the need to run it that long for my rig to be stable for ME..

    If prime fails then back off on the HTT/FSB some until it passes at least 8 hours without errors.

    CONGRATULATIONS !!
    You just found the max mhz of your cpu..
    :)

    Next thing we are gonna work on is finding the max of your ram.. Here is how you are gonna setup for that:

    CPU/FSB Frequency Ratio (CPU Multi) - This we are going to lower to the 7x multi.

    LDT/FSB Frequency Ratio (HTT Multi) - Keep this at 2.5x or 3x just like it was when testing the CPU..

    LDT/FSB Frequency Ratio (Ram Ratio) - Put this at 200 (1/01) so it will be running the same speed as your HTT now.

    CPU VID Control (CPU Vcore) - You can leave this at the same setting you decided to leave it at during your CPU testing.

    Now you have the CPU vcore like it was during the CPU testing, the CPU Multi to 7x, the LDT Multi to 2.5x or 3x, and the RAM ratio set to 200 1/01..

    There is only one more thing that you need to do before testing the ram: Learn about timings!! I’m not gonna go deep into this but I’m gonna suggest what timings are popular with some known types of ram chips. Before you go ANY further I highly suggest you read this ram guide by johnrr6 at DFI Street..

    http://www.dfi-street.com/forum/showthread.php?t=11397

    Its also a good idea to do some research to find out what type of chips your ram use.. It will give you a better idea where to start off with timings and voltages.. Here is a link that might help you find what chips are on your sticks of ram..

    http://xtremesystems.org/forums/showthread.php?t=50010

    Here are some timings I can recommend without getting deep into the full page of memory timings that my DFI board has.. hehe

    TCCD
    CPC- Enabled ( 1T )
    Cas- 2.5
    tRCD- 3 or 4 for more stability
    tRP- 3
    tRAS- 8

    BH5,BH6,VX,UTT
    CPC- Enabled ( 1T )
    Cas- 2
    tRCD- 2
    tRP- 2
    tRAS- 8

    No matter what ram you have timings are never written in stone. They NEED to be tweaked, period ! Always remember that just cuz “Joe Overclocker” says his TCCD runs at 300htt with 8-3-3-2.5 timings doesn’t mean yours will even if it’s the same ram brand, model, revision, production week.

    For more info on RAM, check this thread out:
    http://forums.guru3d.com/showthread.php?s=&threadid=95128
     
    Last edited by a moderator: Dec 6, 2005

  5. THunDA

    THunDA Ancient Guru

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    Time to start testing your RAM !!

    With the above settings you want to start raising the HTT\FSB 5-10mhz, and in between each raise you are going to run about 25 passes of memtest (Test #5 only for now) Once you get errors there are a few things you can do here:

    1- Lower the HTT\FSB until its stable.
    2- Raise the Vdimm (RAM Voltage) to see if that makes it stable, but remember some RAM doesn’t like a lot of vdimm and it could damage them.
    3- Loosen the timings to make it more stable.

    Which option you choose is pretty much up to you and how much you know about overclocking RAM. I can’t stress it enough to read all you can about overclocking because there is so much info out on the net between guides and forums alone.

    Now once you decide what option you are taking, continue testing with memtest #5 until you’re at your max for the ram without errors. Then I would suggest running all the tests in memtest overnight - 8-10 hours.

    If it passes the long test then you want to leave those settings like they are and boot into windows. It might not be stable in windows even if it passes memtest though. I’ve noticed with a64’s that I could pass hours of memtest sometimes but have instability in windows. If you aren’t stable then you need to either give more vdimm, loosen the timings or back off the HTT\FSB some.

    If you do make it into windows I would run 32m SuperPi, 30min OCCT, 3dMarks and then Prime95 overnight, just like we did to finalize the CPU’s max. If it fails any of these you have a few options…

    1- Lower the HTT\FSB until its stable.
    2- Raise the Vdimm ( Ram Voltage ) to see if that makes it stable.. But remember some ram doesn’t like a lot of vdimm and it could damage them.
    3- Loosen the timings to make it more stable.
    4- Settle with what you have so far.

    If you decide to go with one of the options from 1-3 then keep repeating the tests until you are happy and stable.

    CONGRATULATIONS !!
    You just found the max MHz of your ram..
    :)


    Now that you found the max of your CPU and ram it should be a little easier to clock it together..

    Lets say your CPU maxed out at 2800mhz with its default multi of 12x.. But your ram maxes out at 250mhz..

    12x 250 = 3000mhz.. That won’t work ..lol..

    11x 250 = 2750mhz .. That will work but your cheating yourself 50mhz of CPU power.

    12x 233 = 2796MHz .. That will work and get you closer to the max of your CPU. And running the ram little slower then the max you found before to achieve the higher CPU MHz might also allow you to tighten up the ram timings a little.

    Now there is always the option to use a divider for your ram which will get you closer to your CPU and RAM’s max....

    10(CPU multi) x 278(HTT) = 2780mhz (CPU speed)

    If you use a 9\10 divider with this config…

    278 \ 10 x 9 = 250mhz (mem speed)

    Whatever you decide there really isn’t a right or wrong way to do it. The only way to find out which way is best for you to run is test test test!! Run benchies with different configs and see which performs the best.

    This is just a small portion of overclocking.. There is much more to learn but I hope this helps some of you get a better grip on where to start with your A64 system. It took me a lot of time to figure it out myself, it just takes patience.


    Here im gona list some links to things I suggest you read..

    Confused by HTT? LDT? FSB? A64??? READ THIS!
     
    Last edited by a moderator: Dec 6, 2005
  6. MikeMK

    MikeMK Ancient Guru

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    Awesome guide chaps... sure it will help alot of people around here. BTW that vid special spreadsheet with all the values on it is really useful. Been meaning to do one of those myself to save me diving for the calculator all the time. Gonna print that out ;)
     
  7. THunDA

    THunDA Ancient Guru

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    Thanks Mike..

    Yea that chart makes it easy.. got it at dfi-street but its been floating around in a few forums..

    I sure hope this helps some people ..I mean there is alot more to oc'n but I think this is a decent start..

    :)
     
  8. carfunatics

    carfunatics Member

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    I just want to compliment you guys on a fanatastic guide!

    It certainly is the easiest one to understand that I have seen. All the links are a really huge help. Kudos! You guys rule.

    Noticed that you make a lot of mentions about temperature monitoring. Great guide to MBM5 on DFI Motherboards here http://www.dfi-street.com/forum/showthread.php?t=6798
     
  9. THunDA

    THunDA Ancient Guru

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    Thanks for reminding me.. :)

    I use Soundx98's config file myself but forgot to add it .. Gona add it to the guide..
     
  10. rickyboy

    rickyboy Master Guru

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    great guide it worked great got stable overclock but how will this affect lifespan of the components overclocked dont get me wrong i like the extra performance for free but i still need my pc for a couple of years thanks
     

  11. THunDA

    THunDA Ancient Guru

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    Well computer components are made to last 10 or more years, so overclocking it might shorten it a little .. But as long as you dont go crazy on voltage and keep your temps in a acceptable range then you will be fine..

    But of course when it comes to overclocking nothing is for sure..

    Happy the guide helped you.. :)
     
  12. GrAC3R

    GrAC3R Member

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    Ok heres my main Specs:


    AMD FX-55
    OCZ Performance 512x2 2-3-3-6
    Gigabyte K8NS Ultra (F5 Bios)
    500w Antec PSU


    Now I tried the first couple of steps to find my max CPU overclock, but cant even get past 207 FSB without IRQ Blue screens/prime errors (HTT x2 / PCI/AGP Lock on /Ram @ 100 CAS 2.5). So yeah i'm kinda clueless at all this, but what would be causing it to crash with only a small bump ? Do I need to increase the vcore? Any help appreciated.
     
    Last edited: Jun 5, 2005
  13. THunDA

    THunDA Ancient Guru

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    Are you leaving it on the stock multi of 13x ?

    What type of cooling are you using and how are your temps ?

    You can try a different divider like the 133 or 166 .. Sometimes certain dividers might not work correctly, I know some dont work on certain bios versions for me on my mobo..
     
  14. togglemuch

    togglemuch Member Guru

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    So I'm testing my ram right now, and i have the following settings:

    LDT Multi: 3x (default 4x)
    FSB/HTT Freq: 200 (default for 3000+ 939 sckt)
    FSB Multi: 7x (default is 9x)
    RAM Hz: Auto ( I dont know if i should set it to 166 or 200 so i left it auto )
    Timings: 2.5-3-3-7

    It ran MEMTEST plenty of passes, and i want to know before i start upping the FSB if i should lower / up my timings and if it will be stable. I have Kingston Dual Channel ValueRAM and i haven't heard much about its overclockability. I'm pretty new to overclocking so bear with me if some of these questions are elementary.
     
  15. THunDA

    THunDA Ancient Guru

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    The setting you mention "Ram hz" should be set to 200 that seems to be your ram ratio.. setting that to 200 when testing ram is what you want..

    Value ram doesnt 'usually' oc that good but you can go up in small increments and keep testing.. if you dont get far you can also try to loosen the timings to 7-4-4-2.5 .. its not usually good to loosen them too much but if it makes you gain alot then it might be worth it..
     

  16. togglemuch

    togglemuch Member Guru

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    well they come at 3-3-3-8 but i lowered them to 2.5-3-3-7 as i saw someone else was using those timings and i said why not. I'll try loosening timings and such soon :D thanks for the quick response
     
  17. THunDA

    THunDA Ancient Guru

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    ;)

    No problem.. good luck :)
     
  18. togglemuch

    togglemuch Member Guru

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    OK so this is what i've done.

    I tested my CPU to 2200mhz at 5.525 x 8.3% (fsb @ something like 245 x 9 and ram at 100) that was fine.

    I tested my RAM at 225hz at 2.75 v (Ran stable on MEMtest for 17 passes, i assume thats stable?) that was fine.

    So i try running my computer at:

    LDT multi : 4x
    HTT (FSB): 225
    RAM freq: 200hz
    CPU MULT: 9x
    voltages same as above, temperatures are low.

    It boots properly, im in windows, matter of fact im typing this on that setup right above me. Only thing is, i reach to run a Super_Pi test, and i get an error on the first run.

    What could be causing this instability? How should i fix it?

    My ram timings are 3-3-3-8 (My ValueRAM won't allow me to loosen timings beyond stock before i get dots on the screen on boot, which i assume isnt stable :p)
     
  19. THunDA

    THunDA Ancient Guru

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    You mean 1.525 + 8.3% ??

    All you did to test your ram is run 17 passes ? of what test 5 ? the full tests ?

    Try to read through the guide again.. there is more you should do to test your ram then 17 passes of memtest..
     
  20. togglemuch

    togglemuch Member Guru

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    I see. Well, i dont consider overclocking worth it if my RAM can only push it like 100mhz more, probably wont unlock a lot more performance out of my x800xt like i would expect.. and yes i meant 1.525 ;)

    would lowering my ram to 166 then upping the FSB be better? or am i better off at keeping whatever i can get at 200..cause if so im done with this until i can get better ram :/
     

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