llvmpipe os mesa with my own llvm

I have recently built and installed llvmpipe os mesa using my own llvm 
build on a new server. Using my regression tests I've observed that 
varying LP_NUM_THREADS has no affect on performance with this build, but 
it had a dramatic affect on my workstation (60 sec w/ 1 thread down to 
11 sec w/16 threads).  The threading performance should be even better 
on the new server since it has vastly better cpu's each with 8 physical 
cores vs the old 4 core cpus on my workstation. Also comparing outputs 
of run on my workstation and the server this pixels are ~40% different, 
but the result looks pretty close to the eye.

  I'm wondering what can explain the pixel difference and also the 
performance difference?  Could it be that I'm not really using the 
llvmpipe driver? or llvm JIT compilation for my shaders? I am sure 
lvvmpipe and osmesa tracker is built and installed but I'm at a loss has 
to debug further. setting GALLIUM_PRINT_OPTIONS does nothing. Any advice 
greatly appreciated.