Microsoft has announced a new DirectX12 GPU optimization feature in conjunction with Resizable-BAR, called GPU Upload Heaps(opens in new tab), that allows the CPU to have direct, simultaneous access to GPU memory. This can increase performance in DX12 apps/games and decrease system RAM utilization since the feature circumvents the need to copy data from the CPU to the GPU.
See https://devblogs.microsoft.com/directx/preview-agility-sdk-1-710-0/ for full details
AdChoices