Performance loss of a 32bit OS on a 64bit processor

32-bit OS'es, in addition to not being able to use efficiently more than 4GiB of RAM, also can not efficiently mmap() files larger than 4GiB. This last part comes up more often than you'd think.

if you don't have to address memory beyond the 4 GB threshold, you're perfectly fine with a 32-bit OS.

"For a notebook, which has likely less than 4 GB of memory, 64 bit Windows would be overkill. The smart move is to run 32 bit Windows, which also makes it more likely that all drivers work and that most software runs.

Specifically, on e a notebook, you might actually prefer 32 bit Windows' ability to run DOS games.

And yes, 32 bit Windows would actually be faster than 64 bit Windows on most notebook hardware."

As long as you have driver support I would have suggested 64 bit windows as well. You can try it and see if your apps perform any differently. Generally it's been my experience that the 64 bit windows multitasks alot better. I migrated a friend of mine who is a big gamer from 32 to 64 bit and he was able to go from haveing 2 WOW clients open (with framerate issues) to 4 with no issues. Others have changed at my office have had no real difference in performance running office apps.