What's bottlenecking my system?

[JakeDogg777]

My specs:
CPU: AMD Athlon II X4 640 3.20 GHz
GPU: EVGA GTX 460
MOBO: Foxconn A7DA-S 3.0
RAM: 4 GB DDR3 1333 MHz
HDD: 500GB SATA
PSU: ATX-JV 650W
OS: Windows 7 Ultimate 64-Bit

When I'm playing Crysis Warhead on max settings no AA (1280 x 720), I get a max FPS of about 25 - 30 FPS. What's going on? It does the same on Far Cry 2.
I have not OC'd anything yet...

 

[masterasia]

Spinning platter drives are the days of the dinosaurs today.
What kind of hard drive is that? how full is it?