Don't Forget Idle Power Consumption
There is one more thing to be aware of--how those values come together. What do we mean? It's best to demonstrate with an example. Let's assume that after running PowerDirector to encode the H.264 clip we used for this test, we used the system for something else like watching a one hour-long H.264 movie. The system we're using is equipped with the Athlon II X2 250. So, the total power consumption will look something like the table below.
|Header Cell - Column 0||H.264 + Chinese Painting Filter||1 hour of H.264 playback||Total|
|Phenom II X4 955 + Radeon HD 3300||29 Wh||82 Wh||111 Wh|
|Radeon HD 5670||10 Wh||80 Wh||90 Wh|
|Radeon HD 5770||10 Wh||90 Wh||100 Wh|
|Radeon HD 5870 1 GB||9 Wh||100 Wh||109 Wh|
Although previous results showed that total power consumed for encoding is the same for both Radeon HD 5670 and HD 5770, when we take into account idle power (power consumed during video playback), the scale tips in favor of the HD 5670. Even with the Radeon HD 5870, your total power usage is still just a bit lower than the base system.
An End Note
In the beginning, we stated that we believe there's more to energy efficiency than just idle and full load power consumption numbers. After an exhausting number of benchmarks and more than 6,000 words, we come away with a better understanding of how modern graphics cards manage and consume power under different scenarios.
Of the discrete cards tested here today, the Radeon HD 5670 has the lowest power consumption at idle and under load, of course. From a performance-per-watt standpoint, the Radeon HD 5670 consequently holds the upper hand against its higher-end family members, the HD 5770 and HD 5870. The results we saw with Crysis, Cinebench R11, and PowerDVD demonstrate this.
The GPUs populating modern graphics cards have come a long way these past few years. Through smaller manufacturing processes and intelligent board-level and software-based optimizations, each generation of AMD’s GPUs have introduced improvements not just to performance, but also power consumption as well. The Radeon HD 5000-series cards we tested here today are a good example of that.
Oh, wait, this just in:
My next PC will be used mostly for movie DVDs and Diablo 3. Apparently if I get a 5870 1GB I get the best of both worlds - speed in Diablo and low power consumption when playing movies.
How about nVidia cards, would I get the same behavior with a GTX 480 for example?
Next questions: First, where does the HD5750 fall in this? Second, if you do the same kinds of manual tweaking for power saving that you did in your Cool-n-Quiet analysis, how will that change the results? And finally, if you run a F@H client, what does that do to "idle" scores, when the GPU is actually quite busy processing a work unit?
I'd love to see nvidia cards and beefier CPUs used as well. Normal non green hdds too. Just how big of a difference in speed/power do they make?
Thank you for sharing.
Thanks for reading the article.
Have no 5750 sample yet, but they should relatively be close to 5770. For this article, we simply chose the best bin for each series (Redwood, Juniper and Cypress).
The second question, what will happen when you tweak the chip? Glad you ask!! I can't say much yet, but you'll be surprised what the 5870 1 GB can do.
As for NVIDIA cards, I'm hoping to have the chance to test GF100 and derivatives very soon.