http://www.maximumpc.com/benchmarks_what_could_be_amd_r9_390x_allegedly_leaked300#slide-0
 
 
 

 
As you can see from the graphs above, the certain “Captain Jack” graphics card was able to outperform NVIDIA’s latest flagship, the GeForce GTX 980, on a 2560×1440 resolution game tests. The value seems to be the average FPS (frames per second) which is derived from various resource demanding games, like Crysis 3, Metro Last Light, Far Cry 4, Assassin’s Creed and many more. The performance difference seems to be significant and could only be beaten by an SLI or CrossfireX setup. The second graph shows the average graphics cards’ power consumption. And based on the leaked power consumption graph above, the Captain Jack is significantly more power efficient compared to its predecessors. But it wasn’t able to beat the GTX 980 and GTX 970, although the gap is getting closer. The rumor is that "Captain Jack" is either the R9 380X or the R9 390X, although for all intents and purposes, it doesn't matter. One thing is certain this card is from AMD. The "Captain Jack" codename falls (sort of) right in line with past names from the company, which include Hawaii, Tahiti, and even Vesuvius.
 
Here are the rumored "specs" of the 390x and the 380x.