My son and I both have 15-inch Macbook Pro's. Mine is an Early 2011 and his is a late 2011. He has been complaining that his machine was slower than his friend's similar machine and I told him I assumed it was software. He said I was wrong. I installed a fresh version of Mavericks on an external Thunderbolt drive and ran geek bench 64 bit on his and mine started from the same fresh install, external drive. We both have 16 GB of RAM, but his is faster (1333 vs 1600). He has a faster Processor (2.2ghz vs 2.4ghz same gen) and he has a better GPU (6750 vs 6770 both with 1 gb). He gets better single processor speed, but I am getting better multiprocessor speed. Seems like his machine is about 10% slower overall. Anybody able to explain the these results?