According to Microsoft, the Windows 7 operating systems will be a big leap ahead, that will convince the sceptical XP users to upgrade their OS. To retain support for XP-designed applications, Windows 7 will be equipped with an XP mode. This compatibility modus however, uses certain virtualisation functions that aren't present in every Intel and AMD processor.
On Intel's side, none of the Celeron, Pentium Dual-Core, Pentium M and Atom processors are capable of running the XP mode in Windows 7. There's also a number of Core 2 Duo and Pentium D CPUs lacking the virtualisation technology (VT). The affected models are as following:
- Core 2 Duo P7350 and P7450
- Core Duo T1350, T2050/2250, T2300E/2350/2450
- Core 2 Duo T5200/5250/5270/5300/5450/5470/5550/5670/5750/5800/5850/5870/5900
- Core 2 Duo T6400/6570
AMD also has processors that are incompatible with Windows 7's XP mode. Users with an AMD Sempron or older Athlon 64 processor will not be able to use the functionality. The exact list of unsupported CPUs has not yet been announced.

Windows 7 'XP Mode' does not work on every AMD and Intel system
