The R9 M295X is a very elusive Mobility Radeon that has yet to be launched (technically). It does however feature in Apple's new iMac 5k and that means we can get authentic benchmarks for this particular GPU without waiting any longer. R9 M295X is almost certainly based on the Tonga Architecture and will either be codenamed Tonga XT or Amethyst XT. 
AMD's Mobility Tonga GPU Benchmarks Surface - Faster than R9 M290X and GTX 780m
Common sense and precedence dictates that the R9 M295X will be codenamed Tonga XT, but file dumps dating over 4 months back give the R9 M295X the codename of Amethyst XT. Since codenames are not really important this far into a product's lifecycle, we will stick with the obvious nomenclature. Mobility Tonga is based on the Tonga Architecture and is much more powerful than the R9 M290X. It is also more powerful than than the GTX 780m. Sadly however, the reviewer in question wasn't really interested in the GPU of the device and only used Cinebench, a tool which only measures OpenGL performance and unfortunately changes its scoring methods with nearly every iteration. So while we do have the actual legit benchmarks courtesy of Danny Winget over at youtube, our comparison is severely limited. Without further ado, the benchmark and comparison:
There is very little data which I can use to compare results of the Cinebench test. Only benchmarks conducted with the R15 Version will be relevant and no one really uses Cinebench for GPU benchmarking. The only two relevant GPUs that I could dig up were the GTX 780m and the GTX 770. We can also very safely assume that the R9 M295X will score higher than the R9 M290X. The results, everything considered, seem to be pretty impressive. They easily outperform the GTX 770 and the GTX 780m, a very decent desktop GPU and the former mobility champion. The primary problem is that I do not have Cinebench R15 results for the GTX 980M and the rest of the Maxwell Mobility series, so you guys will just have to use your imagination on that. AMD should do an actual launch sooner or later, but before that happens, reviewers should be able to give us the full insight on Tonga R9 M295X GPU.
AMD Radeon R9 M295X Tonga GPU Specs Sheet:
| AMD Radeon R9 M290X | AMD Radeon R9 M295X | AMD Radeon R9 275X | AMD Radeon R9 280X | AMD Radeon R9 290X | |
| GPU Core | Neptune XT | Tonga XT / Amethyst XT | Tonga | Tahiti XT | Hawaii XT |
| GPU Process | 28nm | 28nm | 28nm | 28nm | 28nm |
| GPU Cores | 1280 | 2048 | 2048 | 2048 | 2816 |
| Core Clock | 900 MHz | 800 MHz | ~800 MHz | 1000 MHz | 1000 MHz |
| VRAM | 4 GB GDDR5 | 4 GB GDDR5 | 2-4 GB GDDR5 | 3 GB GDDR5 | 4 GB GDDR5 |
| Memory Clock | 1200 MHz | 1375 MHz | 1375 MHz? | 1500 MHz | 1250 MHz |
| Memory Bus | 256-bit | 256-bit | 256-bit | 384-bit | 512-bit |
| Memory Bandwidth | 153.6 GB/s | 176 GB/s | 176 GB/s | 288.0 GB/s | 320 GB/s |
| TMUs / ROPs | 80 / 32 | 128 / 32 | 128 / 32 | 128 / 32 | 176 / 64 |
#AMD Mobility Tonga benchmarks are out thanks to iMac reviewer. But the choice of synthetic could be better. http://t.co/nGnWhrRKDp
— Usman Pirzada (@usmanpirzada) October 26, 2014
