I am buying pretty much a whole new system buy I wanted to know if EM64T has any downsides compared to an intel not having it. I am debating between Intel Pentium 4 530 Prescott 800MHz FSB 1MB L2 Cache LGA 775 Processor or a Intel Pentium 4 630 Prescott 800MHz FSB 2MB L2 Cache LGA 775 Processor. The 630 is actually cheaper with same clock speed, 1 MB more L2 cache and has more features like EM64T and such, which makes me worry why it is cheaper. I am still on a 32-bit OS (XP pro) and I am curious if there is a down side to a 630 over a 530 in 32-bit operations, thanks.