WPA R9 290X or 7990?

[Pyrex]

I just purchased an 8 GPU 4U rack mount server but I am up in the air as to what cards to run. If I am correct the best card for the cost vs. performance is the R9 290X am I correct? Or should I use 7990s?

Any suggestions?

Thanks

[atom]

290x as it's the fastest single gpu card. dual gpu cards like 7990 or 295x create more problems with heat than you want to think of