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View Full Version : Coolbits 2D underclocking gives higher temps???


coldmist
10-08-04, 12:36 AM
I just got an XFX 6800 GT video card. It runs ~54-55'C at ambient, and middle 60's while busy.

After enabling the newer Coolbits 3D, I went in a wanted to underclock the 2D clock speed so it would run cooler when not playing games.

After looking at the overclock screens, and choosing 250MHz for 2D, I went over to the temp screen, and noticed it had gone up to 67'C. I then went back and just changed it to no overclocking, went back to the temp screen, and it was working its way back down to 55'C.

I did it a few more times to verify the action.

Has anyone else noticed this? Is it by default running 150MHz or something in 2D mode, and choosing anything else clocks it up to get hotter, while not speeding up the fan?

coldmist
10-08-04, 12:37 AM
I forgot to mention, I'm running the 66.81 drivers from nVidia's ftp site (although they aren't listed on the website, they are there).

rewt
10-08-04, 12:53 AM
Theres no reason to underclock 2D. In fact, I overclocked 2D and increased GPU voltage at the same time (thus eliminating core throttling), yielding the same temps (about 42C idle @ 475/1000 1.5vCore as opposed to 42C @ 300/1000 1.2vCore).

Still and again, this may be a bug in 66.81 that nV needs to consider!

Slammin
10-08-04, 08:01 AM
I was going to post about this as well. If I underclock 2-d with coolbits, my idle temp rises.

MaLk^
10-08-04, 08:06 AM
Its propably because the fan is slowing down when underclocking.

But thats just a guess.

Darkoz
10-08-04, 09:35 AM
I just got an XFX 6800 GT video card. It runs ~54-55'C at ambient, and middle 60's while busy.

After enabling the newer Coolbits 3D, I went in a wanted to underclock the 2D clock speed so it would run cooler when not playing games.

After looking at the overclock screens, and choosing 250MHz for 2D, I went over to the temp screen, and noticed it had gone up to 67'C. I then went back and just changed it to no overclocking, went back to the temp screen, and it was working its way back down to 55'C.

I did it a few more times to verify the action.

Has anyone else noticed this? Is it by default running 150MHz or something in 2D mode, and choosing anything else clocks it up to get hotter, while not speeding up the fan?

There's not much to gain by underclocking the 2D mode, you're better off leaving it at default.

Greg
01-11-05, 09:23 AM
I too was going to post about this, very weird behavior. The reason for underclocking would be an attempt to keep the case cooler, or perhaps lengthen the life of the GPU. I certainly get a core rise of 7-10degC and ambient rise of 1-4degC by underclocking almost any amount and no change when overclocking any stable amount.

FallenAngel
01-11-05, 09:52 AM
Actually this is not new to me... I own a Leadtek 6800nu, it never had good idle temps... always in the 60's... until I OVERCLOCKED the 2D clock from 325 to 350 and the idle temp dropped by 10 and the case temp by 2...
Someone told me it maybe due the fan running faster after the OC... but the leadtek has a fixed-speed fan.

My theory is:
Lower clock without lowering the voltage makes the GPU hotter due excessive power... this makes the GPU to trash/dissipate the power in excess under the form of heat.

Not sure about that...

Dr.Nick
01-11-05, 10:30 AM
Yep, I get the same thing. But the best thing to do with the 6800's is to keep the 2D/3D at the same clocks. I mean every GT and Ultra I have tested has always been like that, and probably for a good reason;)