OK so it's the memory bandwidth test that causes the GPU hang, --compute-dp fails with "No double precision support! Skipped", as expected. llvm 3.9 doesn't seemed to be released so I've build the trunk, but the hang is still there. I've been able to capture the logs before the system dies, attached. BTW CLOVER_OUTPUT doesn't seem to be handled, did you mean CLOVER_DEBUG_FILE?