His HD 4830 vs 9600GT/9800GT

9800GT and HD 4830 perform close to each other,both are stronger than the 9600GT

all the cards that you mention will work fine with intel mobo. i don't think there is problem to pair up intel cpu with nvidia cards or ATi cards. the same goes to amd cpu.

as for the card performance it will be like what Maziar mentioned. but i often find that HD4850 is cheaper than 9800GT and the performance is on par with GTS250 aka 9800GTX+

if you're lucky enough you might find cheaper GTS250 than 9800GT

I disklike HIS, I have an ATI 4830 from Powercolor, but i was on a cheap budget. Saphire was always a good company i thought..

I dont know what you have for a budget, but this 4870 for 135 dollars is a steal. http://www.newegg.com/Product/Prod [...] 6814102850

Thank You