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Curbing Your GPU's Power Use: Is It Worthwhile?

Benchmark Results: PowerDVD 9 And Desktop Idle

Hardware-Accelerated Video Playback: PowerDVD 9

Next up is power consumption during H.264 playback using CyberLink’s PowerDVD.

For this test, we swapped the Phenom II X4 955 BE for an Athlon II X2 250. At default clocks, the Radeon HD 5870's average power consumption is about 10 watts higher than the HD 5770. When we lower the operating voltage of the card’s UVD mode to 0.95 V, we are able to match the power consumption of the Radeon HD 5770.

Stop for a second and let that sink in. At the same frequencies and voltage, the power consumption of AMD’s Radeon HD 5870 is the same as a card driven by a GPU almost half of its size.

Power Consumption at Idle

Here we're interested in seeing just how big of a difference there is in idle power consumption between the clock settings we've chosen.

Remember, we're looking at measurements from a whole system drawing power from the wall. Looking at the results, it's quite clear that the Radeon HD 5870 at its default setting offers the lowest power consumption at idle. This is the reason why we wanted to maintain the default idle mode during testing.

At this point, the results speak for themselves. There is a way you can curb the power consumption of high-end GPUs. The easiest and safest way, at least on AMD’s cards, is by tricking them into running at UVD clocks. For the more adventurous, dialing-in a lower voltage for UVD mode (provided the option is available) can offer additional savings or improved performance.

How exactly do you trigger the UVD-specific clocks? You simply need a player or video codec that supports the UVD logic in these cards. Play a video that utilizes the codec, and that's it. You can even pause the video and the card will still stay in UVD mode.

  • hokkdawg
    Dude, I'm now feeling a sudden urge to watch The Matrix!
  • I think, considering those people using SLi and crossfire and higher end videocards, they don't really give a gat about how much elec. they are using. They can afford to buy two expensive PCBs, why would they care about extra 5~10 bucks per month? If poeple are focused on lower power consumption, they would go for lower performance components, arent they?
  • anttonij
    I guess the most important point of this review is that you can lower the cards voltage while running at stock speed. For example I'm running my GTX 460 (stock 675/1800@1.012V) at 777/2070@0.975V or if I wanted to use the stock speeds, I could lower the voltage to 0.875V. I've also lowered the fan speeds to allow the card to run almost silently even at full load.
  • Khimera2000
    @.@ there is no apple @.@

    This is neat though :) I wonder if this article might inspire someone to make an application. Come on open source dont fail me now >.
  • Could you do comparison of "the fastest VC" vs "entry level" and then show us how much money we might end up paying each month or day?
  • the_krasno
    Manufacturers should find a way to implement this automatically, imagine the possibilities!
  • wrxchris

    I have 2 gfx cards pushing 3 displays, but I'm all for saving watts wherever I can. Our society has advanced to the point where sustainability is a very important buzzword that is widely ignored by mainstream media and many corporations, and this ignorance trickles down to the mainstream like Reaganomics. Minuscule reductions such as 30w savings across hundreds of thousands if not millions of users adds up to a significant reduction in carcinogenic emissions and saves valuable resources for future consumption.
  • delinius
    Holy crap, I watched the Matrix again just before this topic was posted..
  • neiroatopelcc
    So when playing video, you risk your amd card going into uvd mode? What models does that apply to?
    I want to know, cause for instance in a raid, I'd sometimes watch video content on another screen while waiting around for whatever there is to wait for. I already lose the crossfire performance because of window mode. I don't want to lose even more.

    Does my ancient 4870x2 support uvd?
  • jestersage
    so... for the dual bios HD6900s, I can RBE one bios with my desired settings and just choose which bios to use before I power up my PC? hmmm... interesting.