I am looking to purchase a Radeon HD 6850, but am not sure what variant to go with (XFX, Asus, etc). I have roughly 24.5cm (9.65 inches) of space length ways, which I know is a little but tight, several verticle slots and about 10.5cm (4.5 inches) width wise. I have 500w PSU with two 6-pin connectors. I don't want to spend more than £140 on this card. It would be great if you could provide a link to the site selling it because I am having great difficulty trying to find one to buy.