OCing vid card?

DyslexicHobo

Senior member
Jul 20, 2004
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I have an X800 Pro with a very nice Zalman heatsink + fan. I was overclocking it to about 25 mhz faster than normal. However, I was told that my motherboard (an asus motherboard, forget which exactly... A8N-X Deluxe, I believe. Rev 1.01) does not have an AGP lock and this could be hazardous to my video card. Can anyone tell me exactly what I'm facing while overclocking my video card without an "AGP lock" (not even 100% sure what this is).

Thank you for any help or explainations. :)
 

jl01

Junior Member
Jul 12, 2006
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having an agp lock is important when overclocking the cpu via front side bus. the agp bus speed is normaly some divisor of the fsb, so when you raise the fsb the agp bus clock will go faster well. while your agp-card likes to get her data 66Mhz it could well be that highjer speeds make her unworkable because the cards gpu clock speed might be derived from the bus clock.

so if you are solely overclocking the card the bus lock is not an issue at all.
 

Lord Evermore

Diamond Member
Oct 10, 1999
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The only problems you'll face will be that the AGP bus will be overclocked if you overclock the CPU bus. The video card may or may not function with very high overclocks, but it might stand a small one. You'll notice instabilities, maybe problems when playing games.

A board that locks the AGP bus just has the AGP and PCI bus speeds set separately from the frontside bus and memory bus, so that you can overclock those while keeping AGP and PCI at their standard speeds.

Asus doesn't list an A8N-X model motherboard. And according to your rig page you have an A8V Deluxe. And no, it doesn't have an AGP/PCI lock, even though the chipset supports it. You might be able to find a hacked BIOS though, that would be one of those features BIOS modifier guys would be certain to try to put in.
 

DyslexicHobo

Senior member
Jul 20, 2004
706
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Hmm... hacked BIOS. Sounds complicated, don't think I want to get into anything too hard.

Anyway, thanks a lot for the info.

Quick question: is there any reason clocking it from it's default (425/450) to about 550/550 would be harmful? It just seems like pretty big increase, but as long as I get no artifacts and the temps stay low I'm good, right?
 

Lord Evermore

Diamond Member
Oct 10, 1999
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Hacked BIOS just means somebody else edited the stock BIOS, and makes the file available, and you flash your BIOS with it the way you would a standard updated BIOS from the manufacturer. People do it to enable features that the manufacturer thought either might affect stability, or just didn't want to have to worry about supporting people playing with weird settings, or put the effort into making it work on a low-cost board.

Just increasing clock speed can't do any harm, besides producing more heat. However if you don't have an accurate heat measurement, you might not realize in time just how hot it's getting. The thermal transfer material also may not be all that great. You will most likely get artifacts that would show you there was a problem developing though. Once you set the higher clock speed, run a benchmark that uses a lot of 3D power and CPU power, like 3DMark05, iand run it in a loop or over and over, and watch for glitches and artifacts, as well as checking the temperature once in awhile.