Poor performance with new SDK

"MichaelNikelsky" wrote:
But why isn´t oculus using adaptive V-Sync?

You're referring to two independent (but related) things: variable vsync and async time warp. The former is when vsync time is delayed when the application is taking longer to finish drawing the frame. The latter is when OVRServer dynamically time-warps based on the most recently completed frame drawn by the application. While the purpose of these two is similar -- to handle the case of the application not making a consistent frame rate -- they achieve it by different means.

There are problems with variable (adaptive) vsync. The first problem is that when the frame becomes visible it is at a time later then the application (and OVRServer time-warp) predicted. This causes a form of judder because timing isn't consistent. Consider a ball rolling across your field of view. If one of the frames was delayed by a couple milliseconds then it would appear as if the ball was very briefly stuck in one position while rolling. It would not roll smoothly.

The second problem with variable vsync is that it would result in inconsistent brightness of the display due to the fact that the Rift display runs with low pixel persistence. If the frame rate were to dynamically drop in half then the Rift display would appear considerably dimmer to the viewer.

As for async time warp, that's a topic you can read about online.