Mesa 9.2 & The R600 SB Back-End Are Good For AMD APUs

While not impacted by the R600_DEBUG=sb optimizations, CoreBreach shows that Mesa 9.2 is certainly much faster for this latest-generation AMD APU over the Mesa 9.1 stable code that is presently relied upon by most Linux distributions. (Again though, our earlier A10-6800K tests were already using Mesa Git master so the 9.2 results are unchanged there until moving to Linux 3.11.)

Nexuiz shows noticeably better performance out of Mesa 9.2 and it's also elevated by using the R600 shader optimizations.