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View Full Version : 6800 GT voltage question....


Phalinx
09-15-04, 08:13 PM
If I had to go by design specifications for the 6800's gpu, how low can the voltage be set to for 2d / 3d and still maintain stability at default clocks?

After reading several posts on this forum, I can assume that 2d is set at 1.1v and 3d is set to 1.3v. Can they each be set to 1.0v? I'm not trying to overclock. I'm just lowering my temps. My core temp is 52c and ambient is 31c. Load is usually around 73c while running rthdribl prog.

I do have a Tornado 92x92x35 mm adjustable fan covering the heatsink and ramsinks. All I did was take off the eVGA cover and turn off the attached fan.

Cheers,

Phalinx

saturnotaku
09-15-04, 08:40 PM
Your current temps are perfectly normal. The 6800 GPU is engineered to withstand heat of beyond 90 degrees. If you're not overclocking, you certainly will not be shortening its life span by leaving the card alone. Besides, tweaking with voltages can bring about some unexpected (and very bad) results. We wouldn't want to see your ruin your investment in spite of your intentions being good.

Phalinx
09-15-04, 09:35 PM
Yes, you are right about not altering the card any further. I don't want to flash the bios. That's a bad idea. I'm just wondering if it is a voltage issue at all. Considering that anything between 50-80c is in design specs, would it be conceivable to think that the considerable amount of heat being generated by the gpu is due to the new architecture/features and not necessarily voltage?

Cheers

Phalinx

Pandora's Box
09-15-04, 09:46 PM
actually the cards are designed to take heat up to 135 degrees, then they start to throttle.

saturnotaku
09-15-04, 09:53 PM
135 = beyond 90

myshkinbob
09-15-04, 10:09 PM
140c is the limit where heat damage can occur, according to a reply someone got from a card engineer, that's why they throttle just below that.

Regarding voltage, i hex edited my leadtek bios and set the voltage to 1.05v for 3D and at default clockspeeds of 350/1000 than ran perfectly stable, however it only lowered the load temperature by about 6-8c compared to 1.3v, at 1.05v load temp around 65c when the ambient was 50c. The voltage seems to affect the core temperature very little compared to a cpu, where undervolting can net massive temperature differences. I'd assume this is something to do with the high transistor count on a graphics core compared to a cpu, as that's where the resistance and therefore heat occurs. Dropping your core speed will net bigger gains, i've found every extra 10 mhz above stock speeds adds a degree centigrade to the core temperature, so i'm assuming the reverse is true also, and a core speed of 250mhz would cause a 10c drop, possibly even more.

Novablade
09-15-04, 11:24 PM
I have been undervolting my BFG to 1.1 for over a week now, and it "does not" lower the temps. Idle and load are still running the same as with 1.3v. fwiw.

myshkinbob
09-16-04, 12:03 AM
you know i just did some testing at 1.2v and 1.15v and you're right novablade, oops :)

The 8c drop is all from lowering my 401mhz core to 350, in fact at 400 with a 1.1v core my temps are up 3c compared to 1.3v, the ambient gets higher. I think maybe the low voltage forces the regulation components to get hotter somehow.

Phalinx
09-16-04, 03:36 PM
So, has anybody underclocked a 6800GT gpu core to see if temps drop, card stability, FPS decreases...etc.

Hmmm. I might try it. Be back in a few minutes

Cheers

Phalinx

Edit: After adjusting the core speed from 350mhz down to 300mhz, the temps went up from 53c to 60c. Ambient went from 33c to 34c. How strange. Maybe the voltage is too much for a lower clock??

Novablade
09-16-04, 10:17 PM
So, has anybody underclocked a 6800GT gpu core to see if temps drop, card stability, FPS decreases...etc.

Hmmm. I might try it. Be back in a few minutes

Cheers

Phalinx

Edit: After adjusting the core speed from 350mhz down to 300mhz, the temps went up from 53c to 60c. Ambient went from 33c to 34c. How strange. Maybe the voltage is too much for a lower clock??


I believe you are right in that the voltage is to high.... already. Thats why when trying to over-volt.... it brings added stress's to the card. Atleast, this has been my experience. When I took the 3d voltage down to 1.1 from 1.3... my whole system has began to run better and has been more stable.

edit: Bare in mind, this is at BFG's stock clock settings of 370/1000. I have not tried to underclock... as I see no reason to. I just think that 1.1v for the 370/1000 is a more viable setting.

Phalinx
09-16-04, 10:31 PM
Novablade,

I haven't removed the heatsink or thermal pads from the ram. I'm thinking that I might remove them and apply AS Ceramique. However, I don't know if there will be a gap in between the ramsinks and the ddr after removing the thermal pads????

Cheers

Phalinx

PaiN
09-16-04, 10:45 PM
Why the hell would someone want to lower a factory voltage??
This boggels my mind. If you think the card has an overheating issue then return it for another or call tech support.....If you just happen to a have irrational fears about(perfectly normal) temps, get with the program folks...and get better cooling.
Again, sorry if I sound harsh, but decreaseing the voltage is just plain dumb...

Pandora's Box
09-16-04, 10:47 PM
Why the hell would someone want to lower a factory voltage??
This boggels my mind. If you think the card has an overheating issue then return it for another or call tech support.....If you just happen to a have irrational fears about(perfectly normal) temps, get with the program folks...and get better cooling.
Again, sorry if I sound harsh, but decreaseing the voltage is just plain dumb...


agreed 110%

Darkoz
09-16-04, 11:04 PM
Why the hell would someone want to lower a factory voltage??
This boggels my mind. If you think the card has an overheating issue then return it for another or call tech support.....If you just happen to a have irrational fears about(perfectly normal) temps, get with the program folks...and get better cooling.
Again, sorry if I sound harsh, but decreaseing the voltage is just plain dumb...

Absolutely, you took the words right outa my mouth, why buy a top end card only to lower it's operating voltage therefore decreasing the card's performance potential?

myshkinbob
09-16-04, 11:05 PM
Why the hell would someone want to lower a factory voltage??
This boggels my mind. If you think the card has an overheating issue then return it for another or call tech support.....If you just happen to a have irrational fears about(perfectly normal) temps, get with the program folks...and get better cooling.
Again, sorry if I sound harsh, but decreaseing the voltage is just plain dumb...

Why is it dumb? isn't it dumb then to throw voltage at a chip to overclock it? I actually undervolted because it improved my situation with regard to the nforce3 and agp fast writes causing lockups above default core clockspeeds. It's not something everyone needs to do, but it does have its uses. I got the cue for from the fact in 2d mode fast writes worked happily, and it seems to have worked for a couple of other people too.

influx
09-17-04, 04:21 AM
Why the hell would someone want to lower a factory voltage??
This boggels my mind. If you think the card has an overheating issue then return it for another or call tech support.....If you just happen to a have irrational fears about(perfectly normal) temps, get with the program folks...and get better cooling.
Again, sorry if I sound harsh, but decreaseing the voltage is just plain dumb...

If you're trying to make your system quieter it can help. Usually lower voltage means lower temps, which allows you to lower fan speeds.
It sounds like it's not helping at all on the 6800 tho. I guess I'll leave my bios alone for now :)

Phalinx
09-17-04, 07:54 AM
PaiN,

It's really simple. I'm not overclocking, but rather trying to maintain a stable card with less voltage. I'm just trying to use default clocks with lower voltage. Less voltage should equal less heat.

I tried lowering the core clock just to see if the temps went down. They did not. Infact, they went up. So, by applying lower voltage (1.0 for 2d and 1.1 for 3d) might make it a little cooler and still maintain stability.

Some of the video card enthusiasts here on these forums like to overclock, raise voltage, and have the fastest card on the planet. Others would like to experiment to see what can lower the gpu core's heat.

Please don't down/bash others on this board for trying something. Show some respect for others ideas and give contructive advice.

Cheers

Phalinx