I think you could get buy on medium settings, worst case scenario you'd have to do low. Not interested in upgrading? Throw in 8GB of RAM and a better graphics card and youd handle it without a problem.
The 4890 is a good card,But I would still recommend you upgrade because the 4890 does not support DX11,Only DX 10.1 so BF3 isn't going to look as pretty as it could.
Ok so my system seems fine then except the gpu would a 6970 be a good decision? I don't really want to get a new one for a year or two. If I evert need more power I guess I can go crossfire in one if these badboys or should I just go for the 6990?