All what Tonga is, is a refresh of Hawaii, it also is GCN 1.2 over GCN 1.1 which Hawaii is, as where TahittiXT2 & Tahiti are GCN 1.0
Tonga can do things Hawaii can't it is newer and is aimed for future AMD products, even that Tonga is more similar to TahitiXT2 over Hawaiii, it's more an inbetween design.
Here some good info on what Tonga offers with it'snew advantages of GCN 1.2:
http://www.extremetech.com/gaming/189034-amd-radeon-r9-285-review-the-gcn-1-2-torpedo-that-takes-out-nvidias-gtx-760 "First, the R9 285 supports TrueAudio, AMD’s superior Crossfire scaling solution, XDMA, and the modified GCN front end that AMD introduced with the Hawaii family. That means eight Asynchronous Command Engines (up from two) and support for four primitives per clock cycle (everything but the R9 290 cards top out at two primitives per clock). AMD claims this will give the R9 285 a huge tessellation performance advantage.." So it could be very possible that the R9 380X will feature a Tonga GPU with a 384 Bit VRAM Bus alike
post edited by Gold Leader - 2014/09/30 02:22:50