I verified that it is supported on this chip by issuing CPUID, EAX=1, and find bit 30 set in ECX. However, when trying the loop below, RAX and CF are zeroed on first call and stay zero forever. I tried same code on an I7-4770K and it works fine, native and in a Hyper-V VM running on that system.
Does anyone know why this wouldn't work on the 4960x? Is something needed to kickstart the hardware rand generator?