x800xl is a good card and to be honest not many games right now run sm3 so you shouldnt be too worried about it. But if you do want a card with sm3 then theres this OCUK brand 6800gt for £258 including vat, which is only £8 over budget. But you also have to include shipping which I think is something like £8. Heres the link. Both are great cards. Also if you look on ebay Im sure you could pick up these cards even cheaper.