(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.