OK, I'll give everyone the needed words to let you understand this game.
You can't Play with Integrated Graphics, you need a actual added VIDEO CARD to your system, or it will not play anything close to be able to enjoy. Also unless you're running at LEAST a Dual core at 2.4 GHz or above, it will also lagg very much.
It's recommended to get at least a Nvidia 8600 or above, and a Dual core to even TRY to play this game.
When I first got Crysis, I had a AMD Dual Core 5400+ at 2.8 GHz and integrated graphics, Game woulnd't play. I upgraded to a cheap, and weak, but ok videocard. a Nvidia 8600GT. I could play on my 22inch LCD screen with all settings at Meduim, and get good enough fps to actually enjoy myself. then I got a 8800GTS and it was much much better.
Also, unless you have a very very good Videocard, DO NOT turn on Anti-Asling. as that will TAX your gfx card very very hard.
I now run with a Quad Core at 3.6 GHz, with a Nvidia GTX260 and 4GB of ram and I still don't get above 60fps unless I lower my resolution.
So Please, don't try to play this unless you have got an actual graphics card, and at least a Dual core CPU.
as to the OP, your e8400 should play this game Fine, anything above 3.0 GHz is only adding very small increases. unless you have the latest and greatest gfx card. with your e8400 and a 9800GTX you should be able to play this game on high, and enjoy it. Very High would be pushing it. I'd recommend overclocking your e8400 to 3.4 GHz or more just for that little extra. above that is not needed at all really.
The cheapest card I'd recommend anyone to buy, at the least is the Nvidia 8600GT. now since things are sooo cheap, get an 8800GT and enjoy the game
Oh and Crysis Warhead, the Parallel story to this one comes out September 16th. I'm exited and already have it purchased and reserved.