Decreasing idle clocks on 4870X2 below 507/500

I ran across a thread at TechPowerUp that was discussing the power saving benefits of decreasing the idle clocks on 4870 cards. I'm a big fan of low idle power utilization, so I got to work attempting to modify my X2's bios with a similar change. I started by decreasing the idle clocks on the slave GPU to 200mhz with RBE (leaving memory alone for now). I flashed the bios onto the card, rebooted the machine, and found that the idle clock was still 507mhz. I flashed back the original bios and it's all working, but I'm a little hesitant to try doing both bioses at the same time without seeing some positive results. I only changed the power saving clocks, leaving the UVD clocks at 507/500. I'm not sure if that would make any difference, but I'd like to have UVD kept at the stock clocks.

Has anyone successfully modded the X2 bioses to have lower than stock idle clocks? If so, what did you do?

--Matt

I flashed both modded bioses onto the card to see what would happen. The base clocks did not drop below the 507/500 clocks that are stock. This time overdrive also stopped working (similarly to what happens when you push the card past the OD limits with another app). Flashed back the originals and it's back to normal again.

--Matt

bad luck... definatly something worth investing your time in to help the community.... good effort, lets hope someone with a little more programming knowledge can decipher the issue....

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Originally Posted by purecain

bad luck... definatly something worth investing your time in to help the community.... good effort, lets hope someone with a little more programming knowledge can decipher the issue....

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Definitely. It sounds like the regular 4870 procedure works pretty well. Maybe it's something that will need to be addressed in RBE. I used 1.18 when attempting this.

--Matt

I was able to flash lower clocks+volts to my 3870x2, sucks that it doesn't work on the 4870x2.

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Originally Posted by cirthix

I was able to flash lower clocks+volts to my 3870x2, sucks that it doesn't work on the 4870x2.

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I just did the mod successfully on my GF's 4870 a few minutes ago too. Worked perfectly and knocked down idle power utilization quite a bit!

Maybe I should sign up on the tpu forums and post there.

--Matt

I'm having a simular problem. I also read that thread on Techpowerup. I did the bios mod and my master HD4870 card is happy with 160/255 @ 1.083v for 2D and 830/1000 @ 1.263v for High 3D. I'm using ATT with automated overclocking for switcheing between 2d and 3D, to go around the problem of screenflashes due to the GDDR5 used. So far so fine.

Then I got me a second HD4870 to be placed together with my first HD4870 so I can run Crossfire. I flashed my second card with the same bios as my first card (e.g. 160/255 - 830/1000 ) The idea was that now BOTH cards run 160/255 in idle and 830/1000 in 3D.... NOT.

Only my master card switches correctly. The second slave card does not switch at all and stays at 750/900 (which is the stock 3d speed) no matter what. How can this be? I 'v moded all the powerstates.
So i have the same problem as you have. The slave card (in your case the second GPU) will not clock down or up. If I switch both cards in their PCIE slots ( master to slave and slave to master) then the card that was formarly the slave and would not switch clocks , now does switch clocks correctly. So the modifiedbios itself is correct.
It's almost like the drivers themselves have somekind of control over the bios settings when running Crossfire

The thing I find the most strange, is that with my previous 2xHD4850 Crossfire setup this worked perfectly!?

Well, I took the advice of a poster at TechPowerUp and removed the Profile.xml for the CCC before rebooting and flashing. I'm able to drop the memory down to 400mhz at idle. If I lower it to 300 windows BSODs when loading the ATI driver. That didn't help lowering the core, but folks have found that lowering the core doesn't net any reduction in power consumption. At any rate, the memory clocked at 400 at idle instead of 500 brought my idle power utilization down from 192w to 181w. I was hoping to get the clock down a little further, but a 10w drop at idle is nothing to sneeze at. I might give 350 a try as well, but I want to run at 400 for a bit to make sure that nothing negatively impacted.

--Matt

350 works! I tried 350 again and found the same BSOD on boot. I tried booting a few times. It seemed to be 50:50 between BSODing and flashing between a blank black screen and a black screen with a cursor in the middle. I flashed them back to 350 and it's been smooth sailing so far.

To get it working I did this:
1) killed CCC.exe and MOM.exe processes
2) deleted the profile.xml for the CCC
3) rebooted
4) flashed the card
5) powered of/on after the flash

--Matt

any drop in temps yet?

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Originally Posted by stangracin2

any drop in temps yet?

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Not really. I'm on water though, and didn't do anything to the GPU clock.

-Matt

Awesome nice work

I did pretty well with 2d clocks.
http://i41.tinypic.com/4lh7c3.jpg
Helped a ton with temps.

One thing I noticed though, the asus 4870x2 oc bios cannot do below ~350Mhz on the ram w/o artifacting the desktop

My palit 4870x2 default bios doesn't have this issue.
Lowest ram I can set is 150, any lower results in green screen.

wow nice stuff greg! (and matt)

what are the final numbers on power draw for you guys?

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Originally Posted by Greg83

I did pretty well with 2d clocks.
http://i41.tinypic.com/4lh7c3.jpg
Helped a ton with temps.

One thing I noticed though, the asus 4870x2 oc bios cannot do below ~350Mhz on the ram w/o artifacting the desktop

My palit 4870x2 default bios doesn't have this issue.
Lowest ram I can set is 150, any lower results in green screen.

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Interesting. I have the asus overdrive profiles installed in my visiontek image right now. I wonder if that has something to do with it. I'll mod a set from the stock bios to see if it makes a difference. That's a huge drop though!

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Originally Posted by SNiiPE_DoGG

wow nice stuff greg! (and matt)

what are the final numbers on power draw for you guys?

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I'm seeing 172w at the wall at idle from an original 192w. I'm going to try some things with the bios to see if I can get further though.

--Matt

I'm not able to get as far as he did, but the stock visiontek bios did allow me to drop the clocks down some. Any lower and I can't get into windows. I'm currently seeing 161w at the wall at idle. That's a 30w reduction overall!

--Matt

excellent indeed :clap::clap::clap:

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Originally Posted by Greg83

I did pretty well with 2d clocks.
http://i41.tinypic.com/4lh7c3.jpg
Helped a ton with temps.

One thing I noticed though, the asus 4870x2 oc bios cannot do below ~350Mhz on the ram w/o artifacting the desktop

My palit 4870x2 default bios doesn't have this issue.
Lowest ram I can set is 150, any lower results in green screen.

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How'd you pull off 1.4a? Are you cutting the voltage down with ATT or something? It looks like 1v is the lowest that can be selected via the bios.

--Matt