AMD Tonga XT Blueprints Surface – Has HSA Support, 384 Bit Bus and 2048 SPs

The Tech Publication PC Watch recently published documents and revealed some facts about the AMD Tonga XT GPU. These were then verified by, who in turn revealed more about the same. This combo has confirmed the original leak that we published some days ago while adding more information on top of it.

AMD’s Full Fat Tonga XT has 2048 Stream Processors with a 384 Bit Bus and HSA Support

AMD’ s Tonga is a very interesting product. It received a very mild reception and was, in my opinion, mistimed and wrongly portrayed. The Tonga XT has 256 more shader count than the Tonga PRO GPU, which means that AMD is using the age old tactic of holding the good stuff back till it is actually needed. The full fat Tonga XT packs a total of 32 compute unit and six memory controllers. Since each is 64 bits wide, it adds up to a 384 bit interface.

Interestingly the GPU supports HSA and GCN 1.1. The configuration is similar to Tahiti. We don’t have any specifics regarding the clock speeds,  but 918 MHz is the reference clock for Radeon R9 285 so we can expect something around 933-1000 MHz for the Tonga XT variant. It is a bit weird that the Radeon R9 285X is featuring a 384-bit memory bus compared to 256-bit bus on its Pro variant but this news is now more or less confirmed. Allegedly, Tonga XT will be shifting to a higher VRAM of 3GB GDDR5.

The Radeon R9 285 is already considered a mid-tier board from its looks and design but the Radeon R9 285X could be a decent update over Radeon R9 280X. Being similar to Tahiti in board design but the updated core with new architecture will leverage the performance and while the Tahiti XT variants have a TDP of 250W, we can might 200W TDP for Tonga XT variants which arrive in September. The pricing for the Radeon R9 285 could fall in between $250 US while the Radeon R9 285X could retail at $300 US. AMD Radeon R7 260X AMD Radeon R9 270 AMD Radeon R9 270X AMD Radeon R9 280 AMD Radeon R9 280X AMD Radeon R9 285 AMD Radeon R9 285X
GPU Core Neptune XT Curacao Pro Curacao XT Tahiti Pro Tahiti XT Tonga Pro Tonga XT
GPU Process 28nm 28nm 28nm 28nm 28nm 28nm 28nm
GPU Cores 896 1280 1280 1792 2048 1792 2048
Core Clock 1100 MHz 900 MHz 975 MHz 933 MHz 1000 MHz 918 MHz TBA
Memory Clock 1625 MHz 1400 MHz 1400 MHz 1250 MHz 1500 MHz 1375
Memory Bus 128-bit 256-bit 256-bit 384-bit 384-bit 256-bit 384-bit
Memory Bandwidth 104.0 GB/s 179.2 GB/s 179.2 GB/s 224.4 GB/s 288.0 GB/s 176.2 GB/s 288.0 GB/s
TMUs / ROPs 56 / 16 80 / 32 80 / 32 116 / 32 128 / 32 112 / 32 128 / 32
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