Downclocking and Undervolting for Desktop Use?

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XacTactX

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Basically, I'm selling my current 6850 because I don't game much anymore, but I also don't want a slowpoke, so that I can still game every once in a while. I'm considering the 4850, 4870, GTX 260, and the like for desktop use. I have my PC on for ~8 hours/day, and 95% of that time is spent in desktop.

Is it possible to downclock and undervolt cards of this nature to reduce idle consumption?

If not, what other cards with similar performance would be good candidates for low power in desktop, but OK performance in games?
 
I'm not sure why you're ever bothering. That 6850 isn't going to net you lots of $$ by time you but another card and is very power efficient.
 
Yes you can do it. I'm not sure if you can do it through CCC or not but I have done it through the bios. I just modified the cards bios so that in 2d mode it would underclock the GPU and RAM while also undervolting it. Then when you fired up a 3D app it would bring the clocks and voltage back to normal. It's really pretty easy to do.
 
kzrider said:
Yes you can do it. I'm not sure if you can do it through CCC or not but I have done it through the bios. I just modified the cards bios so that in 2d mode it would underclock the GPU and RAM while also undervolting it. Then when you fired up a 3D app it would bring the clocks and voltage back to normal. It's really pretty easy to do.
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Beautiful, thank you.

Would this work on reference cards? I'm strongly considering a reference 4850 or reference 4870.

Ultima99 said:
I'm not sure why you're ever bothering. That 6850 isn't going to net you lots of $$ by time you but another card and is very power efficient.
Click to expand...

By selling my 6850 I could get something that is better matched to my current needs and I could pocket ~$80 moving to a 4850 or ~$50 moving to a 4870. 6850 and 460 prices are continuing to depreciate, I'd rather get as much as I can out of the card now than wait.
 
I would check out used hd5750's. They sip energy, and they certainly downclock themselves when in 2d mode.

They can be had for around 70-80 if you look around. That way dx11 is still an option

BTW, i kinda miss the 4860 you sold me, i had it running at 890/900 and it was a champ
 
kzrider said:
Yes you can do it. I'm not sure if you can do it through CCC or not but I have done it through the bios. I just modified the cards bios so that in 2d mode it would underclock the GPU and RAM while also undervolting it. Then when you fired up a 3D app it would bring the clocks and voltage back to normal. It's really pretty easy to do.
Click to expand...

But most modern cards already do this VERY AGGRESSIVELY - they clock down the frequency and voltage to near nothing when not in-use. You used to have to do this yourself, but now modern video cards mostly sip power.

XacTactX, see here just how little your 6850 uses at idle - it's practically nothing!

http://www.techpowerup.com/reviews/HIS/Radeon_HD_6850/26.html

And by comparison, look at the idle numbers for the GTX 260 and 4850/4870 you were considering: they're off the charts because they either had less capable power controls (GTX 260), or the power controls were completely broken (4850, 4870). Believe me, I owned a 4850, and even modifying the BIOS with incredibly low idle voltage and frequency never fixed the problem - it still chewed through power at idle.
 
Your HD6850 is already one of the most efficient at idle, (around 14W). Older generation cards are not tweak for low power at gate level (shut down transistors). This older cards already implement what you are suggesting, the undervolt/underclock in 2D enviroments. You can always get them to work at even lower volts and clocks than their drivers defaults at 2D, but i bet your savings will be minimal and in any case they probably will still consume more power than your 6850.
 
Thank you for the responses so far. I'm very well aware that the 6850 is frugal and miserly in 2D, but it has about twice as much performance as I use currently, and I'm not getting anything out of the investment I made to get it. I'd rather get something with less performance so that I can pocket most of my investment, and still have an enjoyable experience when I game (around once a week now). I really don't mind if my new card uses more power (up to ~25 watts) than my 6850, I just want to save the money for now.

Antiflash made the point that underclocking and undervolting would not significantly reduce idle power consumption from ~40 watts on a 4850. Can you guys confirm this for fact?
 
I tried this with an GTX 285 a couple of years ago (although, only underclocking). Nothing measurable. The thing is the transistors in 2D are doing nothing and the power they consume is only for being "on" (leakage), and less related to the usual power affecting variables as frequency and voltage.
 
XacTactX said:
Antiflash made the point that underclocking and undervolting would not significantly reduce idle power consumption from ~40 watts on a 4850. Can you guys confirm this for fact?
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Yes, did you NOT READ MY POST?

I owned a launch Sapphire HD 4850. The stock clock speeds for idle were incredibly high at 500 MHz core and 750 MHz memory. I installed an MSI BIOS renowned for having the most aggressive idle settings: 160 core, 500 memory, and lower voltage. After I installed it, idle power dropped maybe a few watts and the temperature dropped 1 degree C - obviously you can't do anything about leakage power by adjusting the frequency, and the tiny voltage change wasn't enough to do much.

Idle power clock gating on the 4800 series is just broken.
 
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