(In reply to comment #7)
> Are(In reply to comment #6)
> > Now for your glxgears test: reclocking works (in Portal 2 as well, where I
> > get 58-60 FPS now). The only difference is the radeon.dpm=1 on the kernel
> > command line.
> 
> Are you absolutely sure you need radeon.dpm=1 ?

Yes.

> Reclocking works here (R9
> 290X) without it. I just rechecked and I don't have it on my kernel command
> line (new "drm-next-3.17" branch). Nor do I have it anywhere in /etc.

If unsure with what you've booted, look at dmesg, one of the first lines looks
like:
> Command line: BOOT_IMAGE=/vmlinuz-3.16.0-rc6-citadel root=/dev/mapper/citadel--vg-vol--root ro quiet radeon.dpm=1