I don't think there ever has been one product launch where XFX didn't goof up and leak information. At their website XFX has posted images of the Radeon R9 390X. 

Alongside of it information on an ASUS R9 390X leaked onto he web, confirming what we have been saying for a while now, the Radeon R9 390X is the Hawaii (likely renamed to Grenada) based product re-injected into the 390 series. From ASUS a specs-sheet surfaced on the WWW, the DirectCU II OC model would be clocked at 1070 MHz with its GDDR5 memory running at 6000 MHz (effective data-rate).

If these specs are correct then the 390 is to be merely a fraction faster opposed to the 290X, especially considering this is a factory overclocked OC model. One advantage is that memory is bumped up towards 8GB. But hinestly, we had no problem with 4 GB on the 290X either as it is sufficient already, likely the only thing 8GB will do is once again bump prices on a product that has been out there for quite some time now.

The Radeon 300 series product line will be announced June 16th including the Fiji based Radeon R9 Fury range that will get HBM memory.