32bit means that 2^32 addresses (or 4GB) can be referenced. However, 32-bit Windows (Vista/XP) will only recognize ~3.5GB of ram because the OS need to reserve some addresses for other things such as video memory...
For 64-bit OSes (Vista/XP), 2^64 addresses can be referenced. I don't know how many million GBs that translate to, but you don't need that much memory anyways.
There is no advantage for a gaming rig to use Ultimate. Home premium is enough.
On a side note, I believe that a non-enthusiast PC gamer should order his/her rig from Alienware or Falcon NW.
For 64-bit OSes (Vista/XP), 2^64 addresses can be referenced. I don't know how many million GBs that translate to, but you don't need that much memory anyways.
There is no advantage for a gaming rig to use Ultimate. Home premium is enough.
On a side note, I believe that a non-enthusiast PC gamer should order his/her rig from Alienware or Falcon NW.