Conserve power? Video cards should sleep when idle

[CBRworm]

It seems ironic to me that we have power save modes that will spin down the 8 watt hard drive, turn off the 45 watt LCD monitor, etc - but the video card which draws 100+ watts idle continues to run and draw power even with the display off via software control.

It seems like the video card should be able to go into a 'sleep' mode if the display is turned off due to the inactivity timeout. Maybe there would be an exception if it was being used for stream processing, but . . .

In my case I recently upgraded from an ATI 2900HD to a 4870. The idle power dropped significantly - but this machine runs 24/7. Lots of that time the monitor has timed out. All but one of the hard drives spend a lot of time spun down. but the vent on the back of the video card feels like a hair dryer.

Even in this machine with 10 hard drives the video card draws more power than the drives do.

But, when I want to play a game once every other month, I want it to be fast; for that I put up with the power draw the other 96% of the time.

[theAnimal]

but the video card which draws 100+ watts idle continues to run and draw power even with the display off via software control.

AFAIK there are no video cards which draw 100W+ at idle. HD4870 is only ~60W.

[CBRworm]

Check out the old HD2900 which I just replaced. I would be inclined to run crossfire if it didn't use double the idle power.

Even 60W at idle is a significant amount that could be saved. Also the excess heat from this ~60 watts has to be dealt with in the housing as well as the power supply.

[theAnimal]

Check out the old HD2900 which I just replaced. I would be inclined to run crossfire if it didn't use double the idle power.

2900XT is ~70W.

[Solitaire]

Back then the PC industry had only just been bitten with the Green Bug :D

Nowadays nVidia seems to be too lazy (as usual) to do anything about it, and while some of ATi's board partners have tried their best (my Sapphire HD4830 idles at 160/500MHz even when OCd to 650/1900MHz, and is effectively passive-cooled when idle) ATi have now lumbered them with Satan's own memory - GDDR5. It's fast, but it sucks juice unlike any other (memory) and can't idle. And it accounts for nearly half the power draw on a HD4770... :p

[Zero82z]

The 2900 didn't have proper power management built in. ATI added it to the RV670 revision and continued improving it throughout the rest of the 3000 series and now the 4000 series. The 4890 is especially good since it drastically reduces its clock speed at idle (although even my 4870 goes down to 500MHz from its stock speed of 750MHz).

A 4890 uses only about 40W when idle and a 4870 uses about 65W: http://www.xbitlabs.com/articles/video/display/radeon-hd4890_6.html#sect0

[Solitaire]

That's because Sapphire laughed at everyone and put in really low p-states on their HD4830/50 revisions but made it work. Not the first time a board partner tried going under the 500MHz idle clock but users complained of crashes as the cards didn't get back up to speed fast enough on the initialisation of certain 3D apps. Sapphire got it right somehow with GDDR3 and ATI weren't slow in incorporating the feature into their most demanding 55nm GPU. But there's some fundamental problem with GDDR5 that prevents it from downclocking at all with p-states (at least GDDR3 was always dropped to 1500MHz or less when idle) and no-one's found a way around it yet (maybe one of the reasons nVidia hasn't rolled it out yet) and so while newer cards have GPUs that can downclock very aggressively to save power the situation with memory is now worse - its hungrier than ever and it can't be dropped a single MHz without display issues occuring - even in 2D!

[Per Hansson]

Since this forum sections seems to need a poke I'm bumping this 3 month old thread that is on 5:th place from the top :)

ATI's new 5870 and 5850 cards are quite amazing, due to them using GDDR5 memory they can downclock the memory, and just like Intel and AMD has done for their CPU's for some time now some real transistors on the die has been put to use for conserving power...
Not these previous shitty driver based solutions that always resulted in the card not enabling 3D clocking when you ran a game in Window mode, which would be common for MMO's for example

Result is a card that uses only 19w when idle!

http://www.techpowerup.com/reviews/ATI/Radeon_HD_5870/28.html