Architecture and Specifications
So as you guys know, AMD has been respinning some of their GPUs quite a bit, the oldest one is now 3 years old. In fact the GPU used today is a fully enabled yet tweaked Tonga GPU. Rebadged as Antigua Pro this SKU ended up in the Radeon R9 380. AMD however never released a fully enabled chip, up-to now that is. The GPU housed in the Radeon R9 380X is Tonga XT aka Antigua XT and that means all 32 shader clusters have been enabled.
The Radeon R9 380X is still based on the four year old 28nm fabrication node, 20nm failed and until we see 16 and 14nm viable for big GPUs this 28nm node really is the only alternative. That means that these GPUs will not be the most power efficient. That was the same dilemma for Nvidia with the GTX 900 series of course. Regardless of fabrication, this 28nm GPU is still capable of offering almost 4 TFLOPS of performance to work with. At 28nm AMD applied the latest iteration of their GCN v1.2 iteration 3 architecture.
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| Radeon | R9 Fury X | R9 Nano | R9 390X | R9 380X | R9 370 |
| Fabrication Process | 28nm | 28nm | 28nm | 28nm | 28nm |
| GPU | Fiji | Fiji | Hawaii / Grenada | Antigua | Tobago |
| Streaming Processors | 4096 | 4096 | 2816 | 2048 | 1024 |
| Graphics memory | 4 GB HBM | 4 GB HBM | 8 GB GDDR5 | 4GB GDDR5 | 2/4GB GDDR5 |
| Memory Clock | up-to 500 MHz / 1.0 Gbps | up-to 500 MHz / 1.0 Gbps | 6.0 Gbps | 5.7 Gbps | 5.6 Gbps |
| Core Clock | 1050 MHz | up-to 1000 MHz | 1050 MHz | 970 MHz | 975 MHz |
| Memory Bandwidth | up-to 512 GB/s | up-to 512 GB/s | 384 GB/s | 182 GB/s | 179 GB/s |
| Power Connectors | 2 x 8-pin | 1 x 8-pin | 1 x 6-pin - 1 x 8-pin | 2 x 6-pin | 1 x 6-pin |
| Form Factor | Dual slot | Dual slot | Dual slot | Dual slot | Dual slot |
| Freesync | Yes | Yes | Yes | Yes | Yes |
| DirectX 12 Support | Yes | Yes | Yes | Yes | Yes |
Basically, the GPU is based on 32 shader clusters with 64 shader processors each. So that makes a nice 2048 shader processors in total. These are tied to 32 ROPs and 128 Texture units, which is a good number. Memory sits on a 256-bit wide bus spread over the 64-bit controllers. Antigua runs its memory reference at 1425 MHz which effectively equates to a 5.7 Gbps data-rate. The GPU architecture has remained the same though is comparable to the last-generation products, the cards are PCIe gen 3 compatible.
