How To Overclock Your Graphics Card

Overclocking Nvidia: GeForce 9600 GT

But enough talk – let’s get down to brass tacks. We’re going to show you how to overclock your graphics card using two examples of recent cards – not that overclocking is only possible with new GPUs. It just seemed to make more sense to focus on today’s technology rather than yesterday’s.

Choose your weapons: GeForce 9600 GT and RivaTuner

Geforce 9600 overclockingWe’ll start with a card from Nvidia, a GeForce 9600 GT. This card, which we tested at its recent launch, is based on a G94 GPU, a version of the G92 used in the GeForce 8800 GT and GTS V2 512 MB launched late in 2007. The G92 was itself a version of the G80 in the original GeForce 8800s that hit the market late in 2006. In other words, this is a processor with a well-known architecture and overclocking utilities that have been available long enough for us to become familiar with. The key utility for overclocking a GeForce is RivaTuner (downloadable here), an application that’s been around for some time and that gets its name from the Riva, the first GPU Nvidia produced a few years before the GeForce series. So, RivaTuner is perfectly mature and compatible with all Nvidia GPUs, and it’s updated very regularly. It’s a must-have.

Once you’ve downloaded, installed and launched the utility, click the little arrow to the right of “Customize,” in the second drop-down list entitled "Driver Settings." Select the icon that looks like a graphics card, "System settings."

RivaTuner System Settings

The dialog that opens more or less speaks for itself. You can see three cursors – Core Clock, Shader Clock and Memory Clock.

RivaTuner System Settings Menu

Their function needs no explanation. But we should stop and take a closer look at the second one, for those of you who aren’t familiar with the architecture of Nvidia graphics processors. Since the GeForce 8, Nvidia GPUs have used two different clocks. One affects only the scalar ALUs (the famous stream processors) that form the unified shader units. The other affects the rest of the GPU. By default, these two frequencies are related by a ratio of approximately 2.5 (the ALUs run faster). This value isn’t universal to GeForce 8s, however, since the frequency increases by stages, as we’ll see later on.

Geforce 8 architectureWith RivaTuner, you can increase the Core and Shader frequencies while keeping the 2.5 relation (you can also try changing that proportion). It’s not necessarily worthwhile, but it can give you a few extra MHz, since each portion of the GPU can have different frequency limits. In practice, though, you shouldn’t expect to gain all that much.

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  • jimmysmitty
    I OC'ed my HD2900Pro 1GB to a 850MHz GPU (from 600MHz) and 2250MHz memory (from 1850MHz). So I technically got alomost a 50% OC. But mine is just a HD2900XT 1GB just down clocked.
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  • brendano257
    The HP disk utility asks me for DOS files to write to the disk where would I find these?
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  • randomizer
    Better than the "Overclock your card in 5 minutes" article.
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  • randomizer
    By the way, the first step in Nibitor is to select the device, before you can read the BIOS ;) I'd like to know how you "deleted" the "Extra" frequencies. Did you set them to 0 or did you actually set the number of performance levels to 3 instead?
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  • jojesa
    brendano257 visit www.bootdisk.com and get those files.
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  • randomizer
    A good idea for doing blind flashes is to have a second floppy (with the DOS files on obviously) but add a file called autoexec.bat with the following line in it:

    nvlfash -4 -5 -6 -a -y file.rom

    where file.rom is the filename and it could also be a .bin file. That will flash the card without you having to hope you typed it in right, just make sure you gave it a good minute or two before restarting so you don't corrupt the BIOS.
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  • randomizer
    Typo correction - the line in the autoexec.bat file should read:

    nvflash -4 -5 -6 -a -y file.rom

    Why can't I edit my own comments?
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  • matthieu lamelot
    randomizerBy the way, the first step in Nibitor is to select the device, before you can read the BIOS I'd like to know how you "deleted" the "Extra" frequencies. Did you set them to 0 or did you actually set the number of performance levels to 3 instead?


    Setting them to zero wouldn't work, you have to set them to dash ( - ), as you can see in the screenshot on page 6. AFAIK, Geforce 8 won't boot correctly if you suppress their "extra" performance level.
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  • perzy
    with the really extremly bad cooling on todays GPU's ...a little plastic fan with sleeve bearings that runs slower and slower before it stops completly.. i'm very cautious. New cooling? Yeah, but that costs and then i get a 10% oc. Hmm.
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  • randomizer
    matthieu lamelotSetting them to zero wouldn't work, you have to set them to dash ( - ), as you can see in the screenshot on page 6. AFAIK, Geforce 8 won't boot correctly if you suppress their "extra" performance level.

    It's worth a try, you might get lucky. ;) Besides, you can always blind flash back. Try setting the number of performance levels to 3 (first ticking the "change amount of active performance levels" box of course).
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  • randomizer
    perzywith the really extremly bad cooling on todays GPU's ...a little plastic fan with sleeve bearings that runs slower and slower before it stops completly.. i'm very cautious. New cooling? Yeah, but that costs and then i get a 10% oc. Hmm.

    So you want them to jack the prices up more? We get ripped off as it is until a year after stuff get's released.
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  • radium69
    benchmarks anywhere? i'd like to see performance in gaming benchmarks. Fairly interesting article. Could save me some $
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  • randomizer
    The performance benefit is usually
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  • matthieu lamelot
    radium69benchmarks anywhere? i'd like to see performance in gaming benchmarks. Fairly interesting article. Could save me some $


    Performance is as you would expect it to be : fairly on par with the frequency increase. Don't expect miracles here, but it's enough to climb one step on a manufacturer's performance scale. i.e. our overclocked Geforce 9600 GT was as fast as a regular 8800 GT. Of course you could go beyond that, should you manage to reach higher frequencies than us (better card, better cooling, voltage mod, etc.)
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  • Junkdude75
    My Radeon 2900 pro 512MB,
    went from 507Mhz GPU and 514Mhz memory
    to 846Mhz GPU and 890MHz memory.

    Thank you fore the ispiration!
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  • randomizer
    You got a nice overclock on that 9600GT. Mine won't play nicely in Crysis until I drop to 750MHz. Unfortunately ATITool can't detect artifacts no matter how much they fill the window with yellow, but just looking for them myself I didn't see any at 770MHz. Crysis just caused driver crashes all the time, which fortunately recovered every time. I only have my memory at 936MHz, I don't know how high I can go with that, but probably not far. The same crashes occur with the shader clock above 1770MHz. This was done via rivatuner with 174.74 drivers.

    Just to let you know, the coders of NiBiTor are working on fan control, but they don't have enough 9 series BIOSs (especially 9600GT).
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  • chovav
    I got my 8800GT overclocked from 600Mhz Core to 691Mhz, 900Mhz memory to 1065Mhz and Shaders from 1500Mhz to 1728Mhz. It also ran stable at 700/1100/1750 but I decided to choose a little safer settings to flash the bios with. This overclock of about 17% gave me 16.3% better performance in 3D Mark 06! all that in no time! Thanks guys!!!
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  • ferreguetti
    Well you don't really need a floppy and it's really rare and hard to use it, what I did was, I have a windows 98 installation cd and i used that, works just fine...
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  • randomizer
    It's hard to use a floppy? I find it easier than using CDs, there's one less button to push. They are just real slow.
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