FWIW,
Two years ago I had a few conversations with a guy that built 3-5 machines per week for gamers and local business customers. As you know, gamers typically like higher end machines with higher quality parts -- and **performance** of course!
The guy told me his Intel rep told him that the difference between the CPUs Intel sells in the "retail box" and the ones in the OEM/white boxes was that the ones in the retail boxes passed Intel's QA testing the first time. The rest of the CPUs that are salable get sold in OEM/white boxes after being reworked/fixed (maybe downgraded for speed rating??) and passing QA a subsequent time. This, the guy said, is why the retail boxed Intel CPUs cost a few bucks more.
This is second hand word of mouth, but I do think the guy was relaying truthfully what an Intel rep told him. The guy worked at a place where lots of gamers play each other, renting high end machines by the hour. The guy also would burn in the machines he built for customers for two or three days before delivering them to customers -- can't remember if it was two or three days.
Just figured I would add this for those who might care.
FWIW,
Louis