Please note that our "under load" tests aren't conducted in an absolute peak scenario. Instead, we have the cards running a real game, Crysis 3, in order to show us power draw with a more typical workload.
Yeah, so this is the same test rig in each case; only the graphics card changes. Dropping in the R9 295 X2 raises the total system power consumption at the wall outlet to an even 700W, over 130W higher than with dual GTX 780 Ti cards.
Noise levels and GPU temperatures
The good news here is that, despite its higher power draw and the presence of a water pump and an additional 120-mm fan, the Radeon R9 295 X2 isn't terribly loud at all. This is progress. A couple of generations ago, the Radeon HD 6990 exceeded 58 dBA in the same basic test conditions. I'm not sure I want to see all future dual-GPU cards come with a radiator appendage hanging off of 'em, but I very much prefer that to 58 dBA of noise.
We couldn't log the 295 X2's temperatures directly because GPU-Z doesn't yet support this card (and you need to log temps while in full-screen mode so both GPUs are busy). However, the card's default PowerTune limit is 75°C. Given how effective PowerTune is at doing its job, I'd fully expect the 295 X2 hit 75°C during our tests.
Notice, also, that our R9 290X card stays relatively cool at 71°C. That's because it's an XFX card with an excellent aftermarket cooler. The card not only remained below its thermal limit, but also ran consistently at its 1GHz peak clock during our warm-up period and as we took the readings. Using a bigger, beefier cooler, XFX has solved AMD's problem with variable 290X clock speeds and has erased the performance difference between the 290X's default and "uber" cooling modes in the process. The performance results for the 290X on the preceding pages reflect that fact.
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