So I am upgrading my Alienware M17x laptop graphics cards from dual 4870s to a 5870 (which is dual channeled)so that I can have better graphics and enabled DX11.

I know a decent amount of PC hardware geeky stuff, but I would like some help from you fine people to tell me if I'll be able to run Crysis 1 (which to me looks better than Crysis 2) looking like it does in these videos:
http://www.youtube.com/watch?v=mng8JU692iY
http://www.youtube.com/watch?v=a54R0k-OBtk&NR=1&feature=fvwp

Here are some more specs (please fell free to ask if I missed anything else important):
Quad Core i7 (3.8 ghz)
8GB RAM

*ALSO: I know Alienware computer cost a lot of money, and I did not write this thread to debate anything related to that so please just help me out here. Thanks in advance.

Go with a 6950 if you can. It'd be better IMO. But otherwise, you're hardware seems solid to run Crysis 1 on MAX.

Also, Crysis 2+Ultra Pack graphics looks much better than Crysis 1 MAXED OUT. I'm pretty sure the vids you posted were videos of Crysis 1 but with some graphics mods. Which in SOME cases the graphics in a modded Crysis 1 MAXED OUT looks better or at the level of Crysis 2+Ultra Pack, but the DX11 features Crysis 2 now has.....man.....it really shows that the next generation graphics may actually be here.