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Problem overclocking 6800GT

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Gregory_WE

Member
Joined
Jun 19, 2002
Before you just say that I'm pushing it too far, let me tell you I do not believe that's the case.

Whenever I overclock my 6800GT to ~400/1100 and up, I get freezes in applications (3Dmark, for example, what I use to test it) for a few seconds, and then it "catches up" and continues like nothing happened. I go back down to stock speeds, and it runs just like normal. What is strange is how even if I overclock it farther, I don't get artifacts or tearing or anything like that, it's just this freezing.

In the last week or so I've been playing around with all kinds of settings and it seemed like I had found what worked to fix it, which was to switch the AGP to 4X instead of 8X, but I continued playing around and I can't get it back to where it was, even by doing what I thought I had done (switch it to 4X). No matter what I do now, if I overclock it has random freezes.

I've tried different drivers, I'm using a new PSU which I've tested with a multimeter as completely stable, I do not think the card is getting too hot, I've tried putting the system at stock speeds, yet nothing will fix it.

Is this card getting slower and slower? I'm sure that a while ago I had it running past 400/1100 rock solid stable without any problems, so it leads to be believe that something in my system configuration that changed is the cause of these freezes, not the lack of the ability of the card to run at the overclocked frequencies.

Have any of you encountered anything like this or have any tips for anything to try? Also, would you consider these freezes to be an indication that the card just can't overclock, or some other issue? Thanks.
 
Did you turn off the AGP fastwrites? Additionally, I think that the 6800gt's may require more voltage at Ultra+ speeds, but I am not sure... maybe someone else can confirm??...

Cheers.
 
How are you keeping track of temperatures? It's always a good idea to upgrade the stock cooling when you OC. Have you replaced the OEM TIM with AS5?

As for voltages, I hear a lot of stories about 6800gt volt/bios flash to Ultra with bad results, but that comes with the territory I guess.
 
Yeah fast writes have always been off, if they're on there's a lot of graphical "anomalies".

For temperatures I monitor them using Riva Tuner's hardware monitoring. Idle is around 59C, full load 82C max when overclocked. One thing I notice is that, apparently, when the freezes happen, Riva Tuner reports that the core frequency dips back to 350 MHz, and then jumps back up to 400 when it recovers. So it looks like this... running fine at 400, freeze - jumps down to 350 simultaneously, catches up - jumps back up to 400 simultaneously. It's possible that it COULD be temperatures...

And no, I haven't done anything with the cooler, it's still completely stock.
 
Sounds like some sort of throttling going on... 82C is pretty warm, but shouldn't be throttling yet. Maybe consider some more robust cooling.

Cheers.
 
Hmm this makes no sense now. I just got back from class, set it to 400/1100 in riva tuner, and it's running just fine now... just monitored the temps though and the max got to 86C during testing.
 
Your PSU looks strong... shouldn't be a power issue. What are you using for testing? How long do you let your test run? Personally, I use rthdribl to test max temps for my vid card. 86C is pretty toasty... I would be somewhat concerned.
Back to the card voltage thing... have you done any research into voltage requirements for ultra+ OCing on the 6800gt? It may be something worth looking into, as IIRC, the 6800 ultra does have higher voltage than the 6800gt.

Cheers.
 
Yes it does, but I'm pretty sure that most people get their 6800 GTs to Ultra speeds without having to increase the voltage to the GPU.

For the temps I'm running the hardware monitor that comes with riva tuner that plots out temperatures and clock frequencies and such with respect to time. I just did a full 3DMark2006 run and it hit a new max of 87C, but it ran just fine without any problems.
 
Very curious..... if I think of something else I will post back, but for now, I am a little stumped. Keep the thread updated of anything new.

Cheers.
 
I feel like I don't want to change anything now since it's working like it should.

I just left 3DMark06 running on a loop for the Canyon Flight test for 30 minutes and it got up to 88C, but ran fine.
 
Gregory_WE said:
I feel like I don't want to change anything now since it's working like it should.

I just left 3DMark06 running on a loop for the Canyon Flight test for 30 minutes and it got up to 88C, but ran fine.

If its not broke, dont fix it... good attitude. If you do encounter more issues, feel free to post back and the community will try to help.

Cheers.
 
Restart the computer and it's back to the way it was... freezing once again.

The optimal frequency is detected as 415/1150.
 
This may seem like it is coming out of left field, but have you ran MemTest on your RAM? Best way to do it is one stick at a time, let it run thru at least 12 tests.

Additionally, would it be possible to test the vid card in a different system to see if it does the same thing?

Cheers.
 
chevro1et said:
Did you turn off the AGP fastwrites? Additionally, I think that the 6800gt's may require more voltage at Ultra+ speeds, but I am not sure... maybe someone else can confirm??...

Cheers.

You cant alter the core's voltage on this one, and it also runs at ultra voltage as stock anyway, its exactly the same as the ultra in every way except for differing core/mem clock speeds. The BIOS will not let you change any voltages bar the standard bus voltages which doesnt change performance any
 
Maviryk said:
As for voltages, I hear a lot of stories about 6800gt volt/bios flash to Ultra with bad results, but that comes with the territory I guess.

you have it all wrong, its LE to Ultra BIOS flashing, GT is exactly the same as the Ultra in every way bar differing core/mem clocks, same everything, same BIOS
 
Gregory_WE said:
Yeah fast writes have always been off, if they're on there's a lot of graphical "anomalies".

For temperatures I monitor them using Riva Tuner's hardware monitoring. Idle is around 59C, full load 82C max when overclocked. One thing I notice is that, apparently, when the freezes happen, Riva Tuner reports that the core frequency dips back to 350 MHz, and then jumps back up to 400 when it recovers. So it looks like this... running fine at 400, freeze - jumps down to 350 simultaneously, catches up - jumps back up to 400 simultaneously. It's possible that it COULD be temperatures...

And no, I haven't done anything with the cooler, it's still completely stock.

sounds to me like it is reaching the core threshold and declocking to prevent hardware damage, the core slowdown threshold should be 120 degrees in the forceware panel. If you change to third party cooling you will not get this problem of freezing, its because you are running too hot, 82 degree load is heavy, my 6800 only does 67, 72 in a very hot room. Keep this up and your likely to do some damage, back off the OC slightly or upgrade your cooling. The standard HS on stock cooling also dries up easily to on relatively aggressive OC's. These spikes in core speeds are temperature forced slowdowns, thats why you dont get it on stock, believe me
 
chevro1et said:
Your PSU looks strong... shouldn't be a power issue. What are you using for testing? How long do you let your test run? Personally, I use rthdribl to test max temps for my vid card. 86C is pretty toasty... I would be somewhat concerned.
Back to the card voltage thing... have you done any research into voltage requirements for ultra+ OCing on the 6800gt? It may be something worth looking into, as IIRC, the 6800 ultra does have higher voltage than the 6800gt.

Cheers.

my GT runs nicely at 430/1080 idleing at 56 degrees and loading at 67 avg. temps - try the Zalman Fatal1ty FS-V77 VGA cooler
 
Gregory_WE said:
Restart the computer and it's back to the way it was... freezing once again.

The optimal frequency is detected as 415/1150.

thats a pretty high mem clock on stock cooling, what is the forceware panel reading as idle temps for both core and mem?????
 
Right now it's reading 53C idle for the core, 32C ambient. Can you get the temp for the memory?

But anyways, the odd thing is that it has worked sometimes, sometimes it hasn't, regardless of the temperature. The mem is stable up past 1100 on its own, it's when the core goes past like 385 it seems to start freezing. I'll see if I can run memtest, I don't have any floppies with me or blank CDs, but I have a DVD-RW so I'll see if I can use that.
 
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