Overclocking, Power Consumption, Noise, and Temps
We also spent a little time overlcocking the new Radeon RX 480, to see what kind of additional performance we could squeeze out of it. Before we get to our results, though, we need to talk about an update to AMD's Radeon Software Crimson Edition driver suite for Polaris GPUs that enables a host of previously unavailable overclocking features. With the update, the Overdrive tab is gone in favor of a new tab called WattMan.
Like previous-gen Radeon cards, when boosting, frequencies and voltages scale upwards, power and temperature permitting, based on the GPU's workload at the time. With Overdrive, you could overclock using a fixed percentage frequency offset and bump up the GPU power curve manually. With WattMan, however, while similar tools are still available, users also have the ability to alter frequencies and voltages on a per-voltage step (or state) basis.
WattMan Running On The Radeon RX 480
WattMan didn't cooperate with us fully -- trying some basic overclocks with the GPU percentage slider actually resulted in lower performance -- but we had decent success with manually adjusting GPU frequencies and voltages on a per-state basis, while simultaneously upping the power limit and fan speed. While we had the card overclocked, we re-ran a couple of tests and saw some nice improvements in performance in the games / settings we used. Thief showed a nice jump in performance, as did 3DMark as you can see...
Ultimately, we settled on a peak boost clock of 1300MHz for the top two states, with 2225MHz memory (8.9Gbps effective speed). That's a relatively small increase from the RX 480's default boost clock of 1266MHz, but by upping the power limit, upping the frequencies of the lower steps, and tweaking the fan speed, the overall performance of the card increased quite a bit. We should also note that the GPU temperature remained in the low 70 degree C range, though we had the fan speed cranked up very high. Dropping the fan speed to a lower, and hence quieter, speed would have resulted in higher GPU temps. The overclock allowed the Radeon RX 480 8GB card to overtake the Radeon R9 390 though, so there are some good gains to be had with a little tweaking.
This is a very telling graph. At idle, all of the cards consume a similar amount of power, give or take a few watts. Under load, however, there are some stark differences. The Radeon RX 480 8GB card consumed slightly more power than the GeForce GTX 970. Considering the fact that the RX 480 outperformed the GTX 970 overall, power is right in line. So, the move to the Polaris architecture and a 14nm FinFET manufacturing process allowed AMD to overtake NVIDIA's Maxwell in terms of efficiency. The Maxwell-based GPU on the GTX 970 was manufactured on a 28nm process, however. And if you look at the GeForce GTX 1070, which employs NVIDIA's latest Pascal architecture and a 16nm FinFET process, it used only slightly more power than the RX 480 despite offering significantly higher performance. It seems, at least at this point, AMD was able to produce a part that's more efficient than NVIDIA's previous generation products, but can't come close to NVIDIA's latest Pascal architecture.