Benchmark.blender from blender.org-downloadsection causes the headlineerrors. one on each machine when using GPU Rendering on Titan.
Both Win7profSP1
one: 5960x 16GB
two: Dual Xeon SB-E 64GB
Drivers: actual
Blenderversion: 2.77a
Different GTX Titans were tested in both machines as Primary Videoadapter or (only on Xeon) as secondary Adapter with the onboard as Primary (ASPEED)