The latest build, 400 something. Select a section of the timeline I want to pre render, Shift-M and then select Mp4 1080p 30fps option (same as project settings) Use to work fine until these last two updates.
t may not be noticeable. It seems to work, but no file is created. The size of the created files is 0 kB and at the end no file can be found. Thus, the playback does not run smoothly. At least that's the case with my R9 380. Rendered via CPU, the files are generated and played back correctly.
@matthias-krutz and @OldSmoke my apology, I am wrong. Doing it again, it was quite obvious, I suppose I was going a bit fast and had too many other things going on to recognize my error. Thank You for the correction.