6800 Ultra's Throttling???

[maverik-sg1]

Guys,

Been working on my mates new rig which is DFI SLI with 2x 6800 Ultras, PSU is P&PC510 (lent him mine to try).

They overclock great, up to 475/1250 using watercooling. This clock can be achieved using Riva Tuner, but I use the BIOS flash trick to ensure I dont get throttling, at least that's how I set-up my GT's on my rig.

Problem..... I must get throttling witht eh Ultras (even on BIOS flash) on these as anything over 455/1190 my benchmark scores actually go down.

Anyone else had the same problem with ultra's throttling evenwith BIOS flash??

If you did, what did you do to overcome this issue?

Cheers

Mav

 

[maverik-sg1]

One of the reasons I startyed this thread is that I was considering upgrading to Ultras on my rig.

Getting Nvidia 6800u to run at 475/1250 is a real temptation, but not if the internal throttling can't be bypassed

I dont want to spend £1000+ on 512MB cards if in the end the perceptive overclock (throttled) ends up being no better than my REAL (BIOS set non-throttled) overclocked GT's.

I am sure we have all seen Dazboots get his Leadteks up to 475Mhz - Thats wot I would like to have, but not if Ultra's a auto throttled even with the clock speeds set in the BIOS.

 

[williamc303]

what brand cards u using mate? i guess this is not cold throttling, throttling due to temps falling below 25oC.

 

[maverik-sg1]

Nah temps are healthy at 52 degrees max under load, idle is anywhere between 32 and 44 degrees.

I think they are generic, although they were purchased off ebay with AC5 cooling fitted - removing the HSF revealed it looked like normal reference board.

 

[fatty]

My single ultra which will soon be double ultra's later today does 460/1230 on air it was doing 480/1200 on water thats an asus extreme 6800ultra doesnt appear to throttle at all if I clock it too high it will just drop out of 03 or 05

One thing I forgot to mention duel cards wont clock as high as a single card

 

[Phil Stanbridge]

I get exactly the same here - over a certain point and the 3dmarks decrease dramatically even when the temperature of the cards is perfectly acceptable. My cards were 44 degrees under load, and they began to throttle.

One thing to check with your DFI, there is a bios option for thermal transfer throttle and by default it is set to 50%. Disable it.

 

[maverik-sg1]

Phil,

Good point on the MOBO I will double check the BIOS setting.

These cards seem to throttle after 450mhz, is that around the same as yours?

My clocks are changed using BIOS flash so I would have thought that would not happen, it does not with the GT's but is does with the Ultra's

Fatty,

Thats the same with my GT's (although I cant clock as high as you) but not with my mates Ultra's, I am sure they are not ASUS though - strange one I know.

Mav

 

[K404]

Theres a guy at doomedpc investigating the temerature throttling and hes started working with some guys at guru3d and pooling their cards and knowledge, it seems that the Asus cards use a different temp probe/ pin setup and they dont throttle, or at least, they dont throttle for the same reasons. They`ve got/ tried a lot of ideas between them, can put anyone whos interested in touch if they want, tho it seems Daz and Oppainter have it sorted... so maybe some of you already have the answer!

I`ve had a wee think about it as well coz I got a waterloop here not doin much, was gonna TEC my card.

These ideas arent really based on any experiences but there seems to be a few conditions where the cards throttle. Apparently one condition is (maximum thermal slowdown temp)-100 degrees. which gives a pretty high number. For my card, this gives 45 degrees, which is very close to Phils number. The slowdown threshold should be changeable via Riva, or in the BIOS. Another is the 25 degreee cold bug, but apparently this is sometimes caused by the card thinking its too hot. I was thinking that maybe theres some kind of code bug where the binary/hex or octal forms of these numbers, or the twos complement is the same number, or falls within a certain range that the temp probe doesnt like. Still to look into these numbers and equivalent codes, but I think its worth a try.

Kenny

 

[Minstadave]

I get exactly the same here - over a certain point and the 3dmarks decrease dramatically even when the temperature of the cards is perfectly acceptable. My cards were 44 degrees under load, and they began to throttle.

One thing to check with your DFI, there is a bios option for thermal transfer throttle and by default it is set to 50%. Disable it.

You mean the option labelled "thermal throtteling" or is it a graphics card setting?

Thermal throtteling is just how much the CPU speed is reduced by when in suspend to RAM mode, it shouldn't have any effect on normal use.

 

[maverik-sg1]

It seems this problem is only with the latest revisions of the 6800's

I could BIOS flash my older GT's and achieve higher benchmarks which are relative the the higher clock speeds.

But these Ultra's seem to have a mind of their own, maxxing out at 455ish before some sort of throttling effects the performance.

It's just shame my mate can clock to 475/1250 with no artifacts or glitches and keep them stable at 52 degrees under load that the overclock is not rewarded with higher benchmarks.

Be interesting to see how things progress with the pooled resources of the other guys.

Mav

 

[fatty]

Well bloody ****ylink didnt deliver my second card on friday I have to wait till tomorrow for it grrrrrrrrrrrrrrr

 

[stocky]

I'm also currently experiencing the throttle with an AGP Gainward 6800 Ultra CoolFX. The difference is mine seems to be suffering from the cold throttling - below 25*C. The core is under a watercooled TEC. I have a XFX 6800 Ultra on the way, as the Asus & XFX are suppose to have a different temp monitoring system so they do not suffer from the throttling effect...

The issue is all quite confusing as everyone seems to experience slightly different effects; although I'll hopefully sort it out soon enough.

It would have been nice if nVidia had thought about this before release, as the ATi's do wonders when properly cooled.