Power Saving for VGA Cards...

torrent11 · Post by **torrent11** » Tue Apr 24, 2007 8:31 am

Guys,

I'm in the process of building a better, newer (well bringing me bang up to 2001!

) HTPC.

My current box is a 800mhz MiniITX job, so power consumption problems are probably some of the lowest you can get.

For the new box I've chosen a Dual Pentium 3 1Ghz....
With a Radeon 7500 gfx card.

Looking through the VGA sticky posts I'm shocked by the amount of energy the GFX might consume just in idle mode.

Since the HTPC is likely to be on 24x7 but not actually being used most of the time. Are there any software features (besides sleep) that can reduce this?
For example do the Windows 2K Power saving features turn off the VGA circuitry sufficiently to bring the Radeon's consumption down to zeroish levels?

Cheers

Steve

tay · Post by **tay** » Tue Apr 24, 2007 1:01 pm

All 5900+ series (6000/7000/8000) nvidia cards have a separate 2D clock section in the drivers. You can lower the clock to 200 Mhz or so for htpc use from the usual 400-650.

If you look for this program nibitor (nvidia bios editor) you can also reduce your 2d voltage and force the clock settings in the bios. I have used it before to do just that. ATI fan sites may have something similar. Of course many cards do not allow lower 2D voltages anymore (my 7900GS for eg).

jojo4u · Post by **jojo4u** » Tue Apr 24, 2007 1:36 pm

Yes, you should look out for a card which allows voltage reduction. Radeon X1000-series also allows it, but don't take it for granted.
The situation with graphic cards leaves very much to be desired and is very confusing. E.g. when underclocking some nvidia cards you experience more power consumption since you disable power savings. Or the Geforce 8800 series does not have power savings at all.
I'd recommend to look out for the Geforce 7600/7300 series and check wether they allow undervolting and wether they have all video acceleration you need.

drees · Post by **drees** » Wed Apr 25, 2007 10:36 am

If you can get by with onboard graphics (you're not planning on playing any games), they will have the lowest power consumption.

Worst case if the onboard stuff isn't good enough, disable it through the BIOS and get an add-on card.

AZBrandon · Post by **AZBrandon** » Wed Apr 25, 2007 10:46 am

I did a LOT of testing with undervolting and underclocking. The conclusion was that voltage and clock speed have zero effect on power consumption in 2D mode. Related thread:

viewtopic.php?t=29129

jojo4u · Post by **jojo4u** » Wed Apr 25, 2007 1:29 pm

Well I forgot about integrated graphics, what a shame! Drees is right that you might want to consider them. Especially when they offer nice HDMI output if you can use it. So what do you use you rig for and what connectors are available?

Some links:
http://www.xbitlabs.com/articles/chipse ... 50_13.html
http://www.techreport.com/reviews/2007q ... ex.x?pg=10
http://www.techreport.com/reviews/2007q ... ex.x?pg=10
http://www.digit-life.com/articles2/vid ... o_dec.html

Especially the last article suggests that a fast CPU is sufficent for HD WMV/AVC Video so you don't have to hassle with video acceleration. MPEG2 is more difficult, though.