Honestly I have no idea why your system is performing so poorly and I suggest that you check your drivers if you have not already done so.
Your performance is similar to that of our GeForce GTX 275 which leads me to believe that for whatever reason SLI is not working in Modern Warfare 2 for you. Having no idea how your system is set up I cannot determine if this is a matter of the processors being different or a problem with the graphics card or some other piece of hardware.
On a side note if the title of the article was “Call of Duty: Modern Warfare 2 System Performance” rather than “Call of Duty: Modern Warfare 2 Graphics Performance” then yes I would agree with everything you have said.
Your performance is similar to that of our GeForce GTX 275 which leads me to believe that for whatever reason SLI is not working in Modern Warfare 2 for you. Having no idea how your system is set up I cannot determine if this is a matter of the processors being different or a problem with the graphics card or some other piece of hardware.
On a side note if the title of the article was “Call of Duty: Modern Warfare 2 System Performance” rather than “Call of Duty: Modern Warfare 2 Graphics Performance” then yes I would agree with everything you have said.