I'm just a newbie here, so I hope someone can help me. I never need any feature of Pro that isn't included in the Home version, but if there's no difference in the storage it will take up and the performance is still the same, I'd rather install the Pro version.
There is no performance difference between Home and Pro when installed in the same hardware.. As per as I know atleast..
Maybe a drop. It's mainly a difference of features as pointed out above. There's a more substantial difference in space taken by the OS between the 32-bit (x86) and 64-bit (x64) versions.
After installing windows the performance is the highest. But when you deleting kind of files with programs the performance go down. Like deleting internet cache files or temporary files. The best thing is not to do nothing. It's little similar like our life. One thing I know that boot defrag is increase the performance of windows, but it not for sure.
Rightly said.. Further, as far as I know, the Defrag option of Windows is now a days (post Windows 7) is automatically turned on and works in background when PC seats idle to defrag your boot drive..