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How To Overclock Your Graphics Card

What to Do in Case of Problems

During our tests, we didn’t run into any particular problems. But you can’t always be lucky, and it’s good to know how to react when you run afoul of Murphy’s Law.

Software overclocking: Security!

If you use software overclocking, there’s not much risk. If your overclocking causes crashes, all you need to do is remove life support from the brain-dead application via the Windows Task Manager and readjust to lower frequencies. Sometimes you might have to reboot. At the worst, if the overclocking utilities or the drivers refuse to return to a normal state, uninstalling and then reinstalling them should clear up the problem. That’s the great advantage of software overclocking – everything is easily reversible.

Hardware Overclocking: Cold Sweat Time

Conversely, hardware overclocking – modifying the BIOS – can generate problems that are a little more... exciting. First of all, the frequencies you had decided were stable after a few minutes of testing can prove to be problematic in time. In a case like this, you need to re-flash the BIOS with less ambitious settings.

But that presupposes your graphics card is operating normally. If, for one reason or another, you’ve asked it to run at frequencies that are really beyond its capabilities, then the card may not display anything at all, even during boot-up! In such a case, there are several ways to save the farm. First, have a second graphics card handy. Then all you do is plug it in, and it will handle the display chores while you do a re-flash on the main card. Happy owners of SLI or CrossFire motherboards can use a PCI Express graphics card; the rest of us will have to use a PCI card.

Another solution is to flash “blind.” When you boot to the diskette or USB key to be used for flashing, the sequence is always the same, and after a few seconds you can be sure that the computer is waiting for you to enter a command at the MS-DOS prompt. So all you need to do is enter the same command line as for the first flashing, but with the name of the original BIOS file. (That’s why we made a point of urging you to put that file on the key or diskette along with the modified BIOS file.)

  • 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.
    Reply
  • brendano257
    The HP disk utility asks me for DOS files to write to the disk where would I find these?
    Reply
  • Shadow703793
    To any one interested in modding nVidia BIOS:
    http://www.tomshardware.com/forum/forum2.php?config=tomshardwareus.inc&cat=29&post=246611&page=1&p=1&sondage=0&owntopic=3&trash=0&trash_post=0&print=0&numreponse=0&quote_only=0&new=0&nojs=0
    Reply
  • randomizer
    Better than the "Overclock your card in 5 minutes" article.
    Reply
  • 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?
    Reply
  • jojesa
    brendano257 visit www.bootdisk.com and get those files.
    Reply
  • 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.
    Reply
  • 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?
    Reply
  • 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.
    Reply
  • 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.
    Reply