My friend has an athlon II 3.0 ghz dual core processor with 4gbs of ram... which card is probably the best card to get without wasting money by overkill or bottleneck? He's going to get a new power supply so that is not an issue. BF3 is the goal here.
depends on your friend's budget, psu, display resolution, case - his system specs.
if your friend can, oc the athlon dual with a good cooler and try to unlock other cores.
radeon hd 6850 is a better gfx card than the 550ti. bf3 can be played on both cards. consult this article: http://www.tomshardware.com/reviews/battlefield-3-graph...