Crysis CPU Bottleneck

Hi there guys, I am currently running a GTX 260 on my E6600 @ 3GHz - 4GB DDR800- 680i- 650W OCZ. Windows XP Professional. 32 Bit. Clean install. 191.07 Forceware. Due to circumstances i have no longer got my 1920 x 1080 display and so have been gaming on my 1360 x 768 HDTV in my bedroom. I have been doing some overclocking on my GTX 260 after recently purchasing a Freedom Force VGA Cooler.. While running the Crysis benchmark at high settings testing my cards stability i have experienced something which is quite confusing.... When i run the GPU benchmark at 1360 x 768 0xAA 0xAF i get an average of 52 FPS (Highest 75, Lowest 29) and then when i run the same benchmark.. 1360 x 768 16xAA 0xAF i get an average of 52 FPS ((Highest 75, Lowest 29) The AA is definately on, its set to OVERRIDE application setting in control panel...the figures are all definately correct. Also ive used the r_displayinfo 1 console command to check and sure enough the monitor tells me im running DX9 HIGH SPEC HDR FSAA. Using Rivatuner ive observed my GPU core never goes any higher than 46 degress celsius, it resumes back down to 30 at idle. Do you guys think ive actually hit some kind of CPU or RAM bottleneck? I dont know that much about hardware just a little bit about graphics cards... Any thoughts or observations would be much appreciated. and vsync is definately not on, there is image tearing, and periods where the frame rate surpasses 60FPS... Thanks again guys

Sounds like you are at the limits of what the CPU can do, when you can go back to a higher res run the test again at 19 x 10.