Need help to solve the problem on PC system whether PSU or bottleneck

Check if i have any problem or bottleneck with my computer system

E7400 intel core 2 duo processor
Asrock P45R2000
2x 2gb OCZ 800mhz
1TB 7200RPM SATA HDD
DVD RW WRITER
ATI 5870 SINGLE CARD
3x fans
A big CPU fan, does not look like a gaming CPU fan.
corsair 550w vx

Is there any bottleneck on my system.
i using driver 8.66.
I have problem like game crashing if i overclock, black lines flickering on second monitor if overclocked, blu ray mkv video is not perfectly smooth.

i tested with 3650 and 4770, they working alright with ati catalyst 9.6

Is corsair 850w with 70amps since 10 pound more over than 750w with 60amps, and futureproof.

just only the graphic card 5870,

By how much difference for FPS on games like crysis, need for speed shift, left 4 dead, mirror edge.
If it is bottleneck.

Someone explained that

COMPUTER

CPU "limitation"
40fps 40fps 40fps
CPU---------> GPU----------> monitor ---------> you

VIDEO CARD "limitation"
100fps 40fps 40fps
CPU---------> GPU----------> monitor ---------> you

MONITOR "limitation"
100fps 100fps 60fps
CPU---------> GPU----------> monitor ---------> you

How much FPS you usually get on directx 9, directx 10 and directx 11 games, on CPU side?

Which part of CPU used to prevent bottleneck? Clock speed? FSB speed? Cache?

ususally 4x to 8x dramatically slows down my FPS on 1920x1080. And also Super-sample to Adaptive multi-sample.