if I were you, i'll definately go for the 2.8C, when this C series was newely launched, i came up with 4 diferent types of clock speeds for test in C series, and I havent found out much perfomance difference in 2.8 and 3.0. even I have seen 2.8 out performing the 3.0 in 2 tests (I still wonder Why), but concluding, go for 2.8, its good to buy upto 3.0 range, over that are definately faster.