OCing issues with eVGA 6800GT

I posted a couple of comments in a few threads about this but I figured it would be easier to get some responses if I made my own thread.

I cant OC my 6800GT at all really. I use to be on an Intel setup and when I tried to OC I would get artifacts and cooling wasnt an issue. Now on my AMD64 setup, when I OC 3dmark will lock up for a few seconds than start up again and kill my score and games will just crash to desktop or lockup completely. I have tried turning off fastwrites and setting the 2d and 3d clocks the same and all yield the same outcome. 3dmark will finish through without problems with fastwrites off but games will crash. Im using the 66.72 drivers and I have tried using the 66.81 drivers and they not only dont work but decrease gaming performance for me.

Any and all suggestions are highly appreciated and thanks in advance for any suggestions you might have.

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Is there any sort of "ATi/NV Booster", as a secret option in the BIOS? I know the K8N Neo2 has it. Once I disabled that option my issues with the random freezing <as you described> went away completely.

I havent seen such an option so Im pretty sure that there isnt one. The only thing I have seen related to video cards is fastwrites and agp aperature which I have set at 256.

first, try chaning it to 128mb APT. to see what happens (sounds REALLY weird, but it has worked for a couple of my friends in the past, cant explain it), second make sure that NV silencer is seated on the GPU properly, maybe not enough thermal paste?

I tried the 128mb APT with fastwrites off and was able to OC to 395 because my card hates anything higher than that for some reason. But I recently found out that turning fastwrites off kills cpu performance so I have resorted to turning them back on.

What is really weird though is I tested some things with my vid card and found out that I can OC the memory on the vid card to 1200mhz benchmarkable without any freezes and fastwrites ON. But as soon as I touch the core, it locks up immediately. I want the cpu performance so I would like to try to find a way to OC the core clock with fastwrites on and I was wondering if a bios mod would be something I should try out?

Edit: Yay! This post gave me my second star!

I only found a solution for the freeze problem in game with 6800 and is to put agp to 4x than i can oc my card and the temp drop to 46.

When you dropped to 4x, did your benchmarks or overall performance go down?

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Sounds like you might have an issue with your motherboard OC. Is your AGP lock working ? I read somewhere that having fast writes/side band addressing on might be over loading the HTT bus if your already maxing it out with your OCing. Try reducing 1 step from 4x to 3.5x or similar. Also did you boost the voltages for you chipsets when you OC'd the board ? You might have a chipset that needs more voltage to support your OC with stability.
If you cant resolve by tweaking the motherboard I would reduce all of your OC's back to stock speeds on the motherboard and CPU and try the video card again. If you dont have any problems then your motherboard/CPU OC is causing the problem somewhere.
If its still no good then you just might have one of the cards that just makes it at stock speeds. All cards are different, some guys get lucky some dont. As a last resort you could try boosting the GPU voltage with a BIOS mod to get the core faster and stable. Look here for info and software tools...

http://www.mvktech.net/

most I can do on my EVGA 6800GT without any artifacting is 380/1100.

If I don't mind a little artifacting, then 400/1100.

this on an NF7 v2.0 board.