I never understood it either.
Besides that, would 3MB of L2 cache of 2.4 would make much difference over 6MB of L2 cache of 2.66?
My buddy said to it wouldn't make too much difference unless I'm doing video work. Which I rarely ever do.
do yourself and your wallet a favor and just get the base model. I don't recommend throwing $500 in the trash which is what you'd be doing if you got the supposed "higher-end" model.