Why 64 Bit Windows
Most chosen actual reason:
- Because you payed a lot of money for that new 64 bit processor and feel cheated if you don't use it
- You really have an Applications which needs more than 4 GB of memory. (In most cases: You don't, unless you run a large database or huge self-written scientific applications). Use the system profiler to find out how much memory you actually need.)
- Your System has more than 3,5 GB of memory (3 GB for Windows XP) and you actually need it.
Why not 64 Bit Windows
- Because you don't need it (see above)
- Drivers support is incomplete
- Some applications don't work
- Many programs are installed twice: in the 32bit and 64bit versions, and some plugins work in one, but not the other. Notable Examples: Internet Explorer, Firefox, Explorer
- a 64 bit OS is not faster than a 32 bit OS!
Please note: Most of this is also true for 64 bit Linux.