about to get a new PC from one of the choices on this site http://www.buildyourbox.co.uk/pre-built-pcs, and was wandering if i should go for a 6790 1GB or a GTX 550 Ti graphics card,whats the performance difference if any?
See if you can get them to swap it for a 6850, there isn't much price difference between that and a 6790 and it's a much better card. That rig with the 550ti isn't good, a dual core i3 isn't going to last much longer as a gaming CPU, most games coming out now are recommending quad cores.
You could build a much better PC cheaper than any of those though.