The AMD Radeon R9 Nano was announced during the live-stream even last month. The card will be a small form factor Fiji based solution with 4 GB HBM and air based cooling. 

The product would be 19cm in length, offers 2x the perf of the 290X at half the power - it is now confirmed launching in August.

AMD confirmed this info during its quarter result conference call. It will be the 3rd product deriving from the Fiji range GPUs and follows a mITX form factor. The spec for this product have not been released just yet but expect, hoqwever the it'll be a cutdown Fiji GPU, the original design has  64 ROPs, 256 texture mapping units 64 GCN units with 4096 stream processors. 
 

Based on recent slides the card  offers 2X the performance per watt and 2X the performance density of AMD’s previous flagship, the R9 290X. The product is six inch long with a 175W TDP.