|PC3200 is faster than PC2700 but only if your PC is designed for the faster speed.|
If it isn't, and you fit PC3200 modules, they will only operate at the speed your PC supports.
Some older PCs won't even boot with faster RAM than the PC is designed for, so you need to check that out before buying any. No good buying faster RAM if your PC doesn't support that speed. It's not as simple as that.
To find out what speed of RAM your PC is compatible with, visit the Crucial website and use their system scanner tool "Scan My Computer":