Microsoft has published the system requirements for the Windows 7 Release Candidate which are very similar to those that were given for the beta release. Users who want to install and run the Windows 7 release candidate on their computer system need a computer with the following minimum components:

32-bit or 64-bit processor with at least 1 GHz
At least 1 Gigabyte of computer memory (2 GB for 64-bit systems)
At least 16 Gigabytes of free hard drive space (20 GB for 64-bit systems)
A video card supporting DirectX 9 with WDDM 1.0

Microsoft suggests at least two Gigabytes of computer memory for the Virtual Windows XP mode plus an additional 15 Gigabytes of free hard drive space. The same feature requires a cpu with either Intel-VT or AMD-V as well.

Windows 7 News