Hello, Im playing first person shooter games competitively, and i want as high and stable fps as i can get.
From what i have read, the GPU is the component which increases the maximum fps the system can produce. (But correct me if im wrong.) And if the rest of the system components are poor, especially the processor, the frame rate isn't going to be very stable, and its gonna fluctate a lot.
This is what happens for me, so im wondering if getting a better harddrive have any benefits to a more stable fps? or should i put my money to upgrade my processor instead?

Here is a shot of my WEI if that provides any help:
http://www.2shared.com/photo/MMuT4YGT/WEI.html

My System:
CPU: Intel® Core™ i5-760 Processor (8M Cache, 2.80 GHz.)
GPU: EVGA GeForce GTX 460 1024MB EE (External Exhaust.)
RAM: Corsair XMS3 1333MHz (2 x 2GB + 2 x 4GB.)
HDD: Western Digital Caviar Black 500GB (7200RPM 32MB.)


At the moment, when gaming, i get around 300-100 fps.
The frame rate can be considered high, the problem though is that it fluctates too much, and when it reaches the lowest rate i can feel a considerable increase in control lag compared to when its at etc 300 at the top.
That comes to my question:
What should i upgrade? the processor or the harddrive?
Or can it be something else?

I'd love to see answers on this!
Thanks in advance