saving power with HD 6950/6970

[pokazene_maslo]

Hello. I have a problem with my new Radeon HD6950. I successfully flashed the card with 6970 bios. I'm using 2 outputs from my card - (1.) dual link DVI to 30" monitor (2.) HDMI to my AV-receiver just for sound (desktop at low resolution that I can't see).

The problem is that the card is in idle at 500MHz/1375MHz. What can be done to lower the power consumption? What if I lower the frequencies? Will UVD still work at lower frequencies? How to test if the card is still stable if I lower the voltage at those frequencies?

Any advice?

 

[The Von Matrices]

All AMD cards maintain the higher clocks when more than one monitor is connected. This is normal. I believe that display corruption occurs if you were to lower the clocks with more than one display connected.

 

[VinnieM]

You can try lowering VID1 in RBE. The default is 1000mV and I've lowered it to 900mV. Any lower crashes my system when watching Youtube or anything else that stresses the card enough to go to 500MHz.
Lowering the frequencies might be possible with the latest MSI Afterburner, which allows setting up custom profiles and voltages. Too bad you can't alter it (yet?) with RBE.

 

[pokazene_maslo]

Interesting...

Here is complete table of frequencies and voltages that shows GPU-Z 0.5.1 in single/dual monitor setup with default/6970 BIOS

default bios
single monitor idle 250/150 @0.900v
single monitor uvd  500/1250@1.000v
single monitor 3d   800/1250@1.100v

dual monitor idle   450/1250@1.000v   <- 450MHz core is not even listed in Clock info modes in RBE 1.27
dual monitor uvd    500/1250@1.000v
dual monitor 3d     800/1250@1.100v

6970 bios
single monitor idle 250/150 @0.900v
single monitor uvd  500/1375@1.000v
single monitor 3d   880/1375@1.175v

dual monitor idle   500/1375@1.175v  <- same voltage than in 3D???
dual monitor uvd    500/1375@1.000v  <- lower voltage than in idle???
dual monitor 3d     880/1375@1.175v

Now I don't know what's wrong... GPU-Z? RBE? BIOS?
Does anyone know how to measure the GPU voltage with a multimeter?

 

[Amorpheus]

You can try underclocking manually, it seems that having the second output on at all is enough to trigger the "oh, two monitors, better keep my clocks up" mode. But I don't know of any tools that currently do that; Afterburner allows 50% of default clocks at the lowest and RivaTuner apparently needs an update before it will work with 69xx cards.

Another solution would be to buy a dirt-cheap card just for the additional outputs; I got a 4350 a while ago to hook up my TV as third monitor. Since I discovered that the high idle clocks were caused by using two outputs on my new 6950 I just hooked my second monitor up to the other card.

I believe that display corruption occurs if you were to lower the clocks with more than one display connected.

I ran my 4870 for over a year with a dual-monitor setup and idle clocks at 20% or so. No issues at all. I'm sure there must be some reason why they do that, possibly stability on some setups, but I don't think it should keep anyone from testing it out.

 

[BAGZZlash]

dual monitor idle   450/1250@1.000v   <- 450MHz core is not even listed in Clock info modes in RBE 1.27

I suppose these values are set directly by the driver. Try looking into your XML profile.

Does anyone know how to measure the GPU voltage with a multimeter?

If you ask him kindly, maybe JimmyZ will help you. He knows incredibly much about that suff and is a great guy too.

 

[pokazene_maslo]

I suppose these values are set directly by the driver. Try looking into your XML profile.

Do you mean c:\Users\user_name\AppData\Local\ATI\ACE\Profiles.xml ?
450MHz is not there, only 250,500, and my overclocked 950mhz

 

[BAGZZlash]

Do you mean c:\Users\user_name\AppData\Local\ATI\ACE\Profiles.xml ?
450MHz is not there, only 250,500, and my overclocked 950mhz

Yeah, I meant this one. Strange, in that case I don't know where these 450 MHz do come from... :shadedshu

 

[pokazene_maslo]

BTW. RBE can't open my profiles.xml. Error message says "error loading profile file".

See attachment...

EDIT: GPU-Z definitely reads GPU voltage incorrectly. I was playing with afterburner, changing core voltage and core clock in 3D. Afterburner's HW monitor was showing correct voltage while GPU-Z was showing constant 1.175v.
I reached a stable 915MHz core clock with 1.100v

EDIT2: OK, I lowered VID1 to 0.960v, anything lower hangs my system. Any change in clocks resulted in BSOD on boot.

EDIT3: I tried to measure difference of power consumption of my entire PC, here are the results:
idle single monitor 122w
idle dual monitor 168w
idle dual monitor with lowered VID1 to 0.960v 166w