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

A Quick Gaming Test: Crysis

A Quick Gaming Test: Crysis

After seeing the results we generated using desktop-oriented apps, we were interested to see how badly our modifications would affect gaming performance. Our APAC lab already returned its Radeon HD 5870, so we're sticking to the Radeon HD 6970 for this brief exploration.

We're using the same settings from our last article. We chose the default CPU test under DirectX 9 (with the high-quality preset) at several resolutions (1024x768, 1280x720, 1680x1050, and 1920x1080).

We picked the CPU benchmark instead of the default GPU test for two reasons. First, its point-of-view is closer to the real gaming experience. And second, the average frame rate from this test corresponds well to the performance you see throughout the single-player campaign.

Given the results, it's obvious that higher resolutions are better for testing because they put more burden on the GPU. Keep in mind that the base system’s power consumption with integrated Radeon HD 3300 graphics is about 121 watts. So, between 170 and 180 watts of the 300 watt result we measure is attributable to the graphics card.

If you're willing to take the 15% frame rate hit, you'll get 50 to 85 watts lower peak power consumption. That's a 27 to 55 watt reduction in average power consumption. Lowering the card's operating voltage is the most effective way of procuring those results. Reducing memory frequencies helps a bit too, particularly when it comes to dropping peak power consumption.

The numbers above show that AMD’s Radeon HD 6970 consumes between 70 to 95 watts, which is about half of its original power consumption running at full-speed (170 to 180 watts). If this applies to all games, and not just Crysis, that's not a bad tradeoff. You still get higher, more playable frame rates with the underclocked Radeon HD 6970 than with the HD 5770, and power consumption is about the same.

  • 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.