Overclocking Problem

Hi, I'm running a nVidia GeForce 7900 GS, and I was overclocking it at the "Optimal Frequencies" according to cool bits, and my computer froze up and now for the last day I'm not longer able to overclock my card anymore. Changing the frequency one notch will cause my PC to crash. I've re-installed drivers, updates bios, ect. I'm at the end of my rope here, I feel I've tried everything. When I move the frequency, my screen flashes to a black screen, then normal, then black, ect and eventually reaches the blue screen of death. The card still works fine normally. But it won't let me underclock or overclock... I don't understand why. Any help would be appreciated.

Something is wrong with coolbits then. It's odd...

But .. try to install RivaTuner, and see with that, how it's working.

Good luck- and post back.

Download RivaTuner from here.

Well that's the thing, I forgot to add that I've tried Rivatuner. Same problem. I don't understand. I mean, the card runs fine... I just can't overclock it one bit without the PC freaking out. It crashes during the test on both of the programs.

It can be #1: overheating or #2: the card technically can not run at higher speeds. It's really odd.. generally video cards can be overclocked easy.. but it seems that your 7900GS doesn't wants...

Even if you overclock with +1MHz, then it crashes?

Well, I mean, it's not that it can't, it's that it did, and now it won't... I had it overclocked to the "optimal settings", but now even 1mhz will crash it. Or 1mhz under. And it's temp is running normally (as far as I can tell).

Well if you already overclocked from STOCK to OPTIMAL- that's a huge step. Now it's possible this way, that you can't go higher even with +1MHz.. it's the card's max capability (without voltmod ofc), it can not go higher under normal circumstances.

But it's odd that you can't go lower. You can't even "Reset to defaults" with Coolbits? Tell us the exact BSOD. If you can't read the BSOD, because it automatically restarts- then go to Control Panel -> System -> Advanced -> Performance -> Settings -> Automatically reboot [ ] uncheck it.

Oh, I've already reset it back to normal. It allowed me to do that. So it's at it's stock performance. I'd be happy if I could get it to go back to optimal. Do you want me to try to get the BSOD again? It doesn't automatically restart. It won't be hard to get it lol, it'll be hard to get anything else. Oh, and like I said, as soon as I hit test to test the new settings, it flashes black then normal, black then normal, ect. The screen also gets fuzzy like... well, I wouldn't know the technical term, but it's like you can see colored pixels randomly on the screen.

That's artifacting. Period. For some reasons your card can't hold on those freqs when you click on test.

Well, yes if you can- write here the exact BSOD.. the first few lines, not the whole blue screen.

I couldn't get it to go into the BSOD, but I figured some more stuff out about my problem. I'm still able to move and change objects (with extreme lag), but say when I'm on the desktop after hitting "test optimal frequency", when I right click the desktop, the screen will go black, then when the black screen goes away, a right-click menu will be up on the desktop. You understand? Anyway, I didn't want to run it like that much longer than I did, it just wouldn't crash into the BSOD.

Ok- understood.

Now, you're at stock, try to push up with little increments, like +5 or +10, don't just go ahead with "test optimal"- because optimal, sometimes is wrong. Maybe it was working few days ago, but now the card isn't capable to reach those speeds. So try to increment from stock with little increments, and advance. Benchmark after every little increment (not only with that "test" button), test it with 3dMark03/05 (or even 06).

The screen goes black, and it's lagging, because the card can't hold those freqs (when you click on "test", it'll try to run at those speeds), so one thing is clear, that the optimal frequencies are too much currently for your card.

Maybe I misunderstood something, but then correct me.

I just hit that last time because I wanted to get BSOD, but yeah, I can't go up 5MHZ without crashing... not even 1MHZ. Oh, and should I be pushing the memory and core freq up at the same time?

You know man, it's letting me move it up 1-2 at a time now on core. It wasn't earlier. You think that's because I always tried after trying to set it to my previous working settings and that got the card hot?

Answer to your 1st question: no, you don't need to increase the core and memory clock at the same time.

To your 2nd: well, it's possible. But to make sure, open up your case, check that the fan on video card is spinning, no cables are blocking the airflow inside the case, and maybe even try to 'touch' it, to see if it's hot or not (but this when your pc is turned off).

Even you can try a quick tip. When it's cold morning, open your window, (if you've got air conditioner, then start it), open up your case, and set a large room ventilator/fan to blow fresh air into your case. Then try to turn in the pc, boot up, and try then to increase the frequencies. If it's working now, then it means your card is overheating. Then you need to upgrade cooling, some example for advanced cooling could be NVsilencer.

Nevermind, just try these, and post back.

The fan is spinning (it's quite loud), but it's not spinning all the time. Do you recommend me turning it on where it's constantly on? I already opened the case and put a regular house-fan to the side earlier, but that didn't help. The odd thing is right now I've overclocked it a bit from it's stock settings, and if I go forward, it artifacts, and if I go back on either option it artifacts... I don't understand that... but I'll test it out... if it works, great.

By the way, thank you, you've been very helpful.

Well the video card's fan should be always spinning. That's a must.

Try different settings, overclock, test a lot.. etc. Also you can try to increment with a little step the voltage to the video card. Set it in bios.

You can read this guide about 7900GS, it's interesting. But maybe it just won't work for your card, you need to sort out the problems first. Good luck.