Folks, I've built a few Intel core i5 4690s and I've noticed something odd:

days between finishing P-1 test and then finishing the PRP test and reporting "x is not prime" and then getting a new test:
Intel core 2 duo, 26 days
Athlon II x4 645 3.1 ghz, 18 days
Intel core i5 4690 3.5 ghz, 16 days
Intel core i5 2500 3.3 ghz, 9 days

Why is the i5 2500 faster than the i5 4690?

Whether linux or windoze, about the same speed. There's 3 or 4 boxes of each type cpu, the number of days is an average for that cpu. I've not done anything to tweak the prime95/mprime client. All cpus report 100% use, one client working per core. None are overclocked. Prime95 reports using FMA3 instruction set on i5 4690 while the i5 2500 reports using AVX. The 4690 was way more expensive to build, I would have thought they would be my fastest boxes. What is wrong here? What do I have set up wrong? The Dell I returned (4690) ended up being the same speed as my hand built 4690, so I don't think it was Dell. The problem must be between the keyboard and the chair. But I don't know what.