Power, Temperature, and Overclocking
This board is actually one of the early versions of this particular product. It is pretty common knowledge that AMD and TSMC have improved the production of these chips, and the latest chips run slightly cooler, pull less power, and overclock better. This is just basic progress on a brand new chip that is being mass produced with an eye towards yields and bins. As such an early board, we would expect these numbers to be improved upon by the very latest cards off the line. Still, do not expect miracles with newer boards vs. what I have here. End users should have much the same experience with one or the other, it is only when truly flogging these and testing under lab conditions do differences come to light.
In terms of idle power draw, they are all pretty even. AMD has done a nice job up and down their line to get idle power down to the bare minimum. The older GTX 580 is a bit higher than the rest, but still not bad.
Once things heat up we see some interesting differences. The R7950 is not that much higher than the overclocked R7870 from XFX. The GTX 580 again leads the pack with the highest peak wattage.
In terms of temperatures all of the cards in this review have very stout coolers. We can certainly expect some low temps.
At idle they are all sitting in the 30s. The HD 7950 is a bit higher than the others at 37C, but it is not bad. At load things do change up a bit. The MSI HD 7950 stayed nice and cool at 55C even at full load. I was honestly quite surprised by its performance. The other cards all hit between 65C and 77C, which is well below the 95C that we see many reference designs run at.
Overclocking was interesting with this particular card. At no point did it ever get hot enough to make the fans go much faster than 49%. I raised the voltage slightly to 1.15v, essentially a 50 mv increase. I could have gotten a bit more aggressive and gone to 1.2v, but I did not in this case. I was able to get the core up to 1100 MHz, which is a good 220 MHz increase from the stock 880 MHz speed. This resulted in a very nice jump in overall performance. I was able to increase the memory to 1550 MHz (6200 MHz effective) which gives around 297.6 GB/sec of memory bandwidth.
I believe that by going to 1.2v with the core GPU voltage, 1150 or 1175 is very probable. Get ready for some extra heat though, and while the Twin Frozr III is a very good unit, it will have to spool up to handle that extra heat. So expect some noise from what had been a near silent unit.