The Crysis Warhead system requirements have been revealed at the EA Store. As expected they are pretty much the same as the Crysis system requirements, the only difference is the required HDD space:

CPU: Intel Pentium 4 2.8 GHz (3.2 GHz for Vista), Intel Core 2.0 GHz (2.2 GHz for Vista), AMD Athlon 2800+ (3200+ for Vista) or better
RAM: 1GB (1.5GB on Windows Vista)
Video Card: NVIDIA GeForce 6800 GT, ATI Radeon 9800 Pro (Radeon X800 Pro for Vista) or better
VRAM: 256MB of Graphics Memory
Storage: 15GB
Sound Card: DirectX 9.0c Compatible
ODD: DVD-ROM
OS: Microsoft Windows XP with Service Pack 2 or Microsoft Vista
DirectX: DX9.0c or DX10 More PlayStation 3 News...