As no-one else counters this..... Kawa, as you lack a few biology/science classes..... the human eye sees 16-21 fps as fluent, everything above it the human eye will not notice. Personally I recommend 19-20 fps as most suitable and most fluent but that is just my 2 cents I guess.
Perhaps you should retake the same classes some day? We are not digital machines, but electrochemical and quite analogue. We do not see in "frames". How many frames the human eyes should be exposed to per timeunit for the brain to percieve it as a fluid motion depends entierly on the content of the frame and the method of projection. Fastmoving games without motion blurring will hardly appear anything close to "fluent" at 20 or even 40fps. It also depends on the person seeing, and which part of they eye is seeing it.
http://www.100fps.com/how_many_frames_can_humans_see.htm
http://www.significant-bits.com/framerates-do-matter
My primary gaming monitor just got upgraded from 60 to 120Hz and in fast games without motion blur it's a world of difference.
If we truly saw at such a low "fps", we would all be seeing this effect with a lot of different things: http://www.youtube.com/watch?v=EDTRMauSHSo
And really, Tracker, 2GB graphics memory on a card from late 2008? Its only just now become available on the highend cards from ATI, and only the GTX460 from nVidia. I'd advice Ciroton to try the game and then upgrade incase it was not performing as he wanted.