Eurogamer's Digital Foundry has revealed the specs for Microsoft's next Xbox, codenamed Project Scorpio. Featuring an 8 custom-core x86 CPU clocked at 2.3GHz, a GPU with 40 customized compute units at 1172MHz, 12GB DDR5 memory with memory bandwidth of 326GBs, Scorpio is a beast intended to push 4K gaming and, potentially, VR experiences.
In what may be the most interesting and drastic move surrounds the GPU, particularly the command processor, which is the block of hardware that receives instructions from the CPU and sends them to the graphics core. In some cases developers are seeing their CPU rendering overhead cut by 50%:
"We essentially moved Direct3D 12," says Goossen. "We built that into the command processor of the GPU and what that means is that, for all the high frequency API invocations that the games do, they'll all natively implemented in the logic of the command processor - and what this means is that our communication from the game to the GPU is super-efficient."
Processing draw calls - effectively telling the graphics hardware what to draw - is one of the most important tasks the CPU carries out. It can suck up a lot of processor resources, a pipeline that traditionally takes thousands - perhaps hundreds of thousands - of CPU instructions. With Scorpio's hardware offload, any draw call can be executed with just 11 instructions, and just nine for a state change.
"It's a massive win for us and for the developers who've adopted D3D12 on Xbox, they've told us they've been able to cut their CPU rendering overhead by half, which is pretty amazing because now the driver portion of that is such a tiny fraction," adds Goossen.
