The 290x is a good price, but you will only see maybe 10% improvement over a 290 at 1080p.
Here is a rough comparison of a 290 v 290X. You can see the frame rates are pretty evenly matched.
http://www.anandtech.com/bench/product/1068?vs=1056
Here is a rough comparison of a 290 v 290X. You can see the frame rates are pretty evenly matched.
http://www.anandtech.com/bench/product/1068?vs=1056