Well my specs are as follows:
Dual-Core AMD 4400
2gig Corsair (4x 512 sticks making use of both dual channels)
80gig SATA2 (300) OS Drive with NCQ
160gig SATA2 (300) Games drive with 16mb cache and NCQ
640MB XFX 8800GTS Extreme XXX, PCI-E (x16), Mem 1800 MHz, GPU 550 MHz
Windows XP SP2
Both hard drives were formatted roughly an hour before testing of the game begun, latest NVidia drivers installed.
With the game totally maxed, running at 1440x900 (WS monitor), it runs O.K, perfectly playable, a little sluggish, until you get into a city when all hopes of aiming is gone, as the lag time on moving the iron sites is a good 1-2 seconds. To play this game "effectivly" i belive i would have to run default even with these specs, and for those who havent seen the graphics quality difference between default and high is immense.
Unfortunatley the game dosent make much use of dual-core processors, which is probably bottle necking my system, your actually better off running a higher speed single core performance wise on this game.
So i can only conclude to play this game on high/highest properly you need a cutting edge machine in all aspects.
-EDIT- Oh and before i forget i am refering to the recently released demo, not the full version of the game.
-EDIT-
@Sailindawg
AFAIK there is no SATA III, theres SATAI (150) SATA II (300)