Overclockers Club published a review on the XFX R9 390X
A quote from the article:
The XFX R9 390X does what a next generation card should do. It outperforms the previous generation when it comes to the FPS performance delivered in each of the tests run for this review. Thanks to the improvement in core clock and memory speed over last year's R9 290X, you get a boost in performance that in several cases delivers stock performance between the GTX 970 and GTX 980. It puts the performance versus price of the R9 390X in an odd position of competing price wise with the GTX 980, but competing performance wise in most cases with the GTX 970 that retails for about $80 less than an R9 390X. If you push price to the side you get good playable performance at 2560 x 1440 across the entire test suite.XFX R9 390X Review @ OCC