[Bug 206231] R9 280X low performance with all games

[sylvain.bertrand at gmail.com]

WOW: I did reproduce with dirt rally. I could not see it because the game must
not be restarted to "uncripple" the renderer. I used the number or rendered frames
and I go from an horrible 3000-5000 frames to a wooping 11000 frames, not to mention
the game is now ~playable to max/ultra settings. I had to run 2 times in
a row the benchmark to "uncripple" the renderer, or fool around with the msaa
settings (without restarting).

And I get ~11000 frames with msaax8 or msaaoff (and I can clearly see when it
is on or off).

Since you can reproduce with other games-->Yep, it is very probably a set
driver/weird hardware critical bugs (modulo the numerous visual glitches and
gpu vm faults).

@alex: this one is nasty and probably will ruin the gaming experience (and
benchmarks!) on many games.

(@Jacques: Proton games do not do. Only native GL and/or vulkan, that to remove
any proton bugs)