The US magazine PC Gamer is the first to review C&C 3. It will be featured in the upcoming version of the magazine. They gave it an overall score of 90%, which isn't bad. It's equal to the score that EA's Lord of the Rings: Battle for Middle Earth 2 earned, and much improved over Generals' 78%. Also of importance, the interview notes the system specs for C&C 3 which are:
Minimum: P4 1.8 GHz, 512 MB RAM, 8 GB HD space, DX9.0c 64 MB graphic card with 8X DVD ROM.
Recommended: P4 2.4 GHz, 1 GB RAM, 128 MB video card.
I'd add to that info some advice: if you're going to upgrade your computer to play C&C 3, or if you're going to exceed the specs in one area, the best area to do that in is the graphics card. The best bang-for-your-buck upgrade to improve game performance is definitely in the graphics processing unit, as many Generals players can attest.