they always say the bare minimum to run it, key words there "run it", they dont say "run it perfectly with no lag". 512 RAM is what you need if you want the game to run and play smoothly, also if your using onboard gfx or if you have an old gfx card, might wanna think abotu upgrading them.
Also does your motherbaord have an AGP slot, if yes, read on. If not, get a new mobo with an AGP slot, then read on!
you can get like a 9600XT card and a stick of 256 *making 512* for about £150 now if you look in the right places, and you cant be assed to look far try these.
www.cclcomputers.co.uk - gfx card *if in uk*
www.ebuyer.com - for gfx card if in us/uk
www.crucial.com - RAM
www.repmegood.com -