6800GT throttling?

[Goi]

Hi,
I have an XFX 6800GT 256MB AGP card, and I'm trying to find the max overclock for my card. 405/1100 seems to do fine, and I tried Coolbit's "Detect Optimal Frequencies", thinking that this will give me a conservative base to work with. Well, the detection fluctuates as expected, but seems to give me ~415/1130. However, when I run 3DMark 05 to test for stability, the card seems to throttle for exactly 10s each time. 3DMark 05 will freeze for 10s and the continue. I know it's 10s by observing the 3DMark 05 time counter. Is this throttling, and if so, why is it throttling? I look at RivaTuner's hardware monitoring and see that the clockspeed goes down to 350 from 415 for a period of time, though I'm unable to tell if it's 10s(looks like more though). Temperature when this happens is only in the low 70s.

This sometimes happens in games too(Quake4, CoD2, NFS:MW), and for longer than 10s. However, I tried getting it to throttle by running rthdribl, and it didn't, despite temps reaching the high 70s.

Does anyone know what's going on?

 

[obeseotron]

I ran into something similar a while ago. It really made me mad and I'm not really 100% sure what fixed it. It seemed to be a heat/power thing. Between replacing the cooler with a vf700cu, replacing the case exhaust fan with a panaflo 38mm thick 120mm fan, rewiring for better airflow through the case, flashing the bios to ultra (for higher voltage in 3D), and a fresh installation of windows it was fixed. I'm really sorry I can't be of more help but I really don't know exactly what the problem was. At this point I'm still not back up to the 434/1160 the card did at first, totally stable for months, I'm still stuck at 420/1145. At the very least I would say clean your cooler, a lot of dust builds up and can really degrade cooling performance. Better yet get a Zalman vf700cu.

 

[Goi]

I can circumvent the problem by using RivaTuner to set the startup speed to whatever overclocked speed that I want, and then locking the speed to always be at 3D performance mode, but that's not really what I wanna do since I also wanna have a lower clockspeed for 2D mode. Alternatively, I can modify the BIOS's throttle speed to that of my 3D speed so that even when it throttles, it does it to the same speed, but since I'm still in the process of finding out my max speed, this isn't an option. I guess I'll use the 1st method for now until I find the max, then flash it to make it permanent. Still, it's a problem that bugs me and apparently many other 6800GT owners. I wonder what makes it throttle, since it's obviously not the temperature.

 

[Powermoloch]

Try go back to stock speeds and see what happens.

 

[Goi]

It doesn't throttle at stock speeds. At least, I don't know if it does, since it's always throttling back to the stock speed anyway which is 350. I've managed to use the RivaTuner method to overclock all the way to 420/1140 so far without throttling, and the card is stable with good temperatures, so I really don't know why it's throttling otherwise.

 

[1EZduzit]

I just bought a used 6800GT. What kind of temps should it run? I haven't tested it in anything hard yet, only Tibes, original and it runs 63C. I need to download 3Dmark and try that.

Rivatuner? I don't want to OC, but that sounds like a nice way to watch the temps when testing. Right now I just open it in the properties window on the second monitor.

 

[Goi]

Well, my idle/load temps are ~50/75 give or take. RivaTuner's hardware monitor is a nifty way of monitoring clockspeeds, voltages and temps, and has a logging function which is useful. 63C is a really good load temp if that's actually what it is. I suppose yours isn't throttling since you're running it stock?

 

[1EZduzit]

Yeah, I'm not much for overclocking video cards. It's also cool down here in the basement, 34C ambient temp. I don't think Tribes is working the card very hard either.

 

[Goi]

Yeah well, anyone else?

 

[Navid]

Originally posted by: Goi
I can circumvent the problem by using RivaTuner to set the startup speed to whatever overclocked speed that I want, and then locking the speed to always be at 3D performance mode, but that's not really what I wanna do since I also wanna have a lower clockspeed for 2D mode.

The GPU and memory heat up only when they are stressed regardless of clock frequency. I mean if your card is stable under stress at the clock speeds that you have chosen and there are no freezes, the temperatures will drop when you stop a 3D application and go to 2D even if you always keep the clocks at the same frequency.

 

[imported_Soldier]

Im not so sure what your describing is a video card stall, it sounds more like a system ram stall. What do you have your AGP port set to? 64? 128? Try changing the size to one setting higher. Also its possible you have too much stuff on a 470w power supply. 4 harddrives and a dvd burner with a gig of ram and a 6800gt is a lot to power. You do have the GT on its own rail right? The 6800 series cards are power hogs and dont take well to sharing with other components on the same rail...

 

[Goi]

Navid yes I know that.

Soldier I don't think that's the case, simply because when I force the clockspeed to be 3D performance mode all the time with RivaTuner and then overclock with that setting, I get no throttling/stalls at all, and I am currently at 420/1150 stable. If I didn't lock it, then it would throttle/stall as low as <400MHz core. If system ram/power was an issue, then it would stall regardless of me forcing the clockspeed to 1 setting. Because of this I'm inclined to believe it's a video card issue. I tend to think that 470W from Enermax is plenty for my system.

 

[JRW]

The pauses during 3dmark indicate overheating , I used to have this issue when I had a 6800GT , The only way to fix it is to either lower the clock speeds or get better cooling on the card.

 

[Navid]

Originally posted by: Goi
Navid yes I know that.

Then, why not just use RivaTuner? I don't understand!

You know that you cannot set a different memory clock speed between 2D and 3D for an Nvidia card anyway, don't you? So, it is only your GPU running at higher clock speed at 2D. As long as you are sure that your card is table while running a 3D app, it should have no problem running a 2D application.

 

[Goi]

JRW I thought that was the case until I monitored my temps with RivaTuner and found that the max it even went to was the 70s, and this throttling seems to happen independent of temps. I could run 3DMark05 and it would throttle at 70C, but then I run rthdribl and it wouldn't throttle even if temps reach the high 70s.

Navid, like I said I would like to continue separating 2D mode from 3D mode rather than using 3D mode all the time. I'd like to keep my heat, temps and noise down for the 90% of the time when I'm not gaming or using some other 3D application. RivaTuner wouldn't let me do that. Modifying my BIOS would, but I see it as more of a hack. I'd like to know why it's throttling, and if it's a known problem. So far I've read quite a couple of people experience this problem, but it's not widespread, and so I'd like to know why certain people who o/c are experiencing it, and not others, and if there's a possible fix other than the ones I've mentioned.