I'm after a nvidia GeForce GTX 560 Ti Graphic Card but I see there are a few to pick from, not sure what the difference mean.
http://www.overclockers.co.uk/productlist.php?groupid=701&catid=1914&subid=1341
http://www.overclockers.co.uk/productlist.php?groupid=701&catid=1914&subid=1341