Stuttering on COD 6 Modern Warfare 2

[Mikaka]

Here's the problem, whenever I turn (as in move mouse left/right) in this game, it freezes for a second, and most of the time I end up dead. I don't know what's the cause of that, but on the box of my graphics card I read that it requires 450W, but I have only 400W. Could this be the case, because I have some stuff inside computer.

Ingame settings:
1440x900
Antialiasing x2
Textures: Automatic
Every other effect: On

What's inside:
Gigabyte GA-P35-S3
Intel Core2Duo Q8200 @ 2.33GHz
3GB Ram 800
HIS ATI Radeon HD 4850 512MB
Sound Blaster XFI Gamer
Realtek Wireless G card
2 Harddrives and DVD
400W

Is it possible that 400W isn't enough to run all of this?? Crysis also suffers, when there's fast change in scene (like turning, or some door just opened).

 

[Mikaka]

Sorry, its Core2Quad Q8200 @ 2.33 GHz
And its running on Windows 7 Ultimate x64

What's with the forum not allowing to edit post??

 

[Mikaka]

That's what can I read from the PSU:
+3.3V 20A
+5V 14A
+12V1 14A
+12V2 13A
-12V 0.3A
+5VSB 2.5A

 

[wa1]

Try to update your vga driver and see if it work...

 

[leon2006]

Scale down your game settings then gradually bring it up to the point you get stable performance.

Update the gpu driver. So far 9.10 is working well.

 

[Mikaka]

Ok I'll try scaling down the settings.

I already had 9.10 driver. I tried to update to 9.11, but game started crashing. When map is loading, you see the bar below. When bar goes to the end (means finished loading the map), game crashes instantly with no error. I tried reinstalling the game, but it didn't helped, the only thing that did is reverting back to 9.10 driver.