8800GTS 640 vs9800GTX 512

It'd be a good deal but it wont future-proof you.
I'd make it depending upon how much would I get for my gts 640.

if his card 9800gtx+ that will be good deal
even 9800gtx are a bit better then 8800GTS but not that much see this
http://www.techspot.com/review/92-asus-geforce-9800-gtx...
i suggest go for HD 4830 that better then GF9800GT and closer to GF980GTX+ ($79.99 after $10.00 Mail-In Rebat)
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

it's cheaper then that used 9800GTX and at the same performance
http://techreport.com/articles.x/15752/4

lol 1440 x 900 crysis max settings can be done with ATI 4870 or GTX 260  

There is the AA also u see.

I'd say a 9800 can run crysis on 720p high settings and 2 x AA.

The article you linked to is benching the 8800GTS 512, not the 8800GTS 640. The 512 is a G92 core, the 640 is a G80 core . . . a pretty big difference. Although the 512 has less memory, it has 128sp and higher core and memory clocks. The 512 runs all over the 640. The 9800GTX and GTX+ are basically the direct replacement for the GTS 512, with the same # SP and higher shader, core, and memory clocks.

The 9800GTX(+) would greatly outperform the OP's 8800GTS 640, but if you are looking to buy a card to use for the next year or more, a GTX260 would be a better use of the money, but is by no means future proof.

Just my two bottlecaps . . .

@ SNURTLE112: Ask your friend if he`ll let you test it first.
I do n`t think you`ll see a huge improvement, an improvement yes, but not a huge one, for `future proofing` you really should be looking at a GTX260 or 1Gb HD4870 (and yes, I mean the 1Gb not the 512 Mb card).

I guess i will wait awhile then and purchase a 260 in 6-9 months when the prices drop some more.Like i said right now i can play crysis with some AA and enthusiasts level at 1440x900 with playable frames over 30fps.so i guess i will sit tight.thanks for the info. Anyone got an idea on how much prices might drop on the 260's?And im sorry when i say future proof i mean for the next couple years on the same 1440x900 monitor, which i know shouldnt be TO difficult since the resolution is not high at all

Sounds like a sound plan to me.
As for price drops, all we can do is wait and watch.

thanks for all the help ONCE again