The point I was making for using 64x with 4g of ram is that 32x wont use more than ~3.25g of RAM due to the system allocating RAM for hardware addressing. 64x allows all 4G of ram to be used.
The upgrade Advisor should inform you of what CPU you have and if it is 64x compatible. Good info!
I'm familiar with the limitation of 4 GB memory addresses in 32-bit. I was just mentioning that a 64-bit capable CPU is needed to even install a 64-bit OS.
Jasin, technically that's illegal. The key that came with the box is intended for use with ONE computer, not one computer per disc. Read the EULA and any information that came in the box...