Really, that low 
It's not much better than my 5850 ~280Mhash/s.
It's not much better than my 5850 ~280Mhash/s.That's 333 per core and the 6990 has 2 cores. Just in case it's not clear.
There's some deals (good?) on the cards on eBay:
http://shop.ebay.com/i.html?_from=R40&_trksid=m570.l2736&_nkw=Bitcoin+ready
5850's are dual core'd aswell (unless im totally fucking wrong and im thinking of the 5950)