8 Changes in Windows 8 That Will Drive You Nuts
Microsoft has stated any PC capable of running Windows 7 can run Windows 8, for which the system requirements remain unchanged. Don't let the minimum specifications fool you though. Even if that serviceable P4 machine you have runs nicely at 3GHZ (far faster than the 1GHz minimum requirement), there's a good chance you won't be able to take it along for a ride on Windows 8.
Starting with the consumer preview, only processors supporting PAE (Physical Address Extension) and No eXecute (NX) bit can run Windows 8, which the installer throws in your face if it isn't detected. While that's not an issue for most modern processors, Intel didn't implement NX bit tech in their processors until late in the P4 Prescott era. That leaves a number of (still decent) Northwood, Gallatin, and Pentium M based computers in the lurch. All of them can run Windows 7 just fine, but get the middle finger from Windows 8.