https://bugs.freedesktop.org/show_bug.cgi?id=98693
--- Comment #5 from Alex Deucher alexdeucher@gmail.com --- (In reply to Jani Kärkkäinen from comment #4)
"The game I'm testing needs 3.4 GB of VRAM.
Setups: Tonga - 2 GB: It's nearly unplayable, because freezes occur too often. Fiji - 4 GB: There is one freeze at the beginning (which is annoying too), after that it's smooth.
So even 4 GB is not enough."
Also the descriptions of the problem seem to match mine. A problem in memory handling?
The freeze at the beginning is most likely shader compilation. Mesa does not have a shader cache yet.