As with our other next-gen API tests, we kept Doom's graphics settings identical to those for OpenGL. The only change we made was to turn on Vulkan.
Yow. In our average FPS measure, the Radeon RX 480 gets a 45% boost from the move to Vulkan at 1920x1080, and it comes darn close to delivering 99% of its frames at 90 FPS or better. Recall that we're running the game at the Ultra preset with 8X TSSAA .
The RX 470 isn't quite as fast, but it beats the GeForce GTX 970 in both performance potential (as measured by average FPS) and ties it for smoothness (as measured by our 99th-percentile frame-time metric). The GeForces end up just a bit worse off than they were with OpenGL, so there's no real advantage to enabling this next-gen API for Maxwell GPUs, at least. Seems we need to get one of them newfangled GTX 1060s for our test bench to conduct a fair fight.
After a second round of retesting, the Radeon R9 380X also got an appreciable performance boost from Vulkan. For some reason, our first test run pegged the card at 59 FPS, while a second test with the Radeon Software 16.8.2 hotfix driver raised that figure to a quite-respectable 87 FPS. The card's 99th-percentile frame time also improved from a troubling 28.4 ms to a much happier 15.7 ms. To keep the playing field equal, we re-ran every Radeon card above using the same drivers, though neither the RX 470 nor the RX 480 demonstrated any meaningful changes in performance from that update.
After our re-testing of the Radeon cards above, none of the cards spend any time beyond the critical 50-ms or 33.3-ms thresholds, and only the GTX 960 spends a noticeable amount of time working on frames that drop its average under 60.
To see any meaningful struggles from our top three cards, we have to click over to that 8.3-ms plot again. The Radeon RX 480 8GB card comes darn close to delivering a perfect 120-FPS experience at 1080p with Doom's Ultra settings. It spends just three seconds of our one-minute test run on frames that take more than 8.3 ms to render, and that translates into an amazing Doom experience.
The RX 470 spends about three times as much time working on tough frames past 8.3 ms, so it's in a close race with the GTX 970. The Radeon R9 380X does slightly worse still, while the GTX 960 brings up the rear by a wide margin.