Problems with Turok (2008)

Ok so I bought this game recently and have been trying to play it but it's just pi**ing me off, not because I think its hard because I like that about it although I think it would be a little easier if I had more than 25 bloody fps!

I've checked the requirements for it and they're well below my pc specs (i think). I run the game at 1680x1050 on the recommended quality for my pc which happens to be all at full.

I'm running an Intel quad core @ 2.44ghz. An ATI HD4800 series 512mb and 4gb of ram yet i cant get any more than 20-25 fps.

I mean i can play Crysis at 1440x900 at very high quality and get at least 60 fps... is this game just badly coded or something?