32-Bit vs. 64-Bit Windows
Basically a 32-bit processor can only see your access up to 4 GB of RAM. Go beyond 4 GB of RAM in a 64-bit CPU.
Most Windows XP versions are 32-bit but there is a 64-bit special version of Windows XP. Starting with Windows Vista, Windows is offered in both 32 and 64-bit versions. Because Windows 7 utilizes extra available RAM to cache the hard drive, it’s best to get six or eight gigs of RAM and go Windows 7 64-bit.
A Closer Look at 32-Bit vs. 64-Bit Windows
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