I'm running the latest mesa and kernels from git and I think I may have
encountered this issue

Everything works fine using i965, using prime with R600_LLVM=1 is also ok
however when running with R600_LLVM=0 I got similar error messages about being
out of memory 

This seemed to happen when I was testing out the highest settings of WoW -
disappointingly the i965 had the highest fps