@neo_the_one: U must be talking abt Pine.....The 5900 u got is a underclocked version of the 5900 card. Its christened the 5900XT. Personally i wud have gone for a 9800pro with a 15k budget, but then since u have already got the card it doesnt matter.
Well the cost difference is sometimes due to the quality of the add-in boards, quality of the components, and the software bundle ! All of these go towards adding to the final cost. For eg: A asus fx5200 costs 4k upwards but comes with a good software bundle with 2 full games and a dvd software, the xfx F5200 retails @ 3.2k and comes with only a driver cd and a measly manual.
@Raven: Pine manufactures XFX brand cards, and the 6800 series frm them has among the best price/performance ratio currently. XFX has started gaining a lot of popularity since the 6XXX series.