Haswell/Broadwell CPUs have a hardware bug.
 
Intel has quietly started to disable TSX instructions in Haswell and early Broadwell processors, something the company candidly revealed to a group of US-based technology journalists during a meeting last week.
The set of Transactional Synchronisation Extensions allows developers to decide how the CPU resources are allocated to multi-threaded applications, and it seems that the errata was unearthed by a third party and subsequently confirmed by Intel.
But rather than recall the parts, Intel decide to disable the TSX instructions via a microcode delivered straight to the manufacturer's motherboard.
 
Does Sonar utilize the TSX instruction set ? If so hows does disabling TSX affect multi-core or multi-thread performance in Sonar ?

AFAIK, the more common Haswell 4770K does not have TSX enabled anyway. The 4790K does enable it so the TSX bug applies to this chip . Of course, this is the one I am looking at buying (Devil's Canyon). The Haswell E's seem to enable TSX as well.
Noel, can you or another Baker chime in here ? If Sonar uses TSX, I really do not want to spend $330 on a chip that does not and I will wait for Skylake.

You may want to PM Noel directly and link this thread to make it easier for him.