Currently, this new HDR support is quite limited though. No major Linux desktop environment actually supports HDR yet, so you will have to use Gamescope specifically with it. When paired up with vkd3d-proton version 2.8 or newer, it "will allow D3D12 games to detect and use the HDR10 color space if they support it". It's also only supported on AMD GPUs, and even there it needs special Linux kernel patches.
One that perhaps is more exciting, because pretty much everyone will benefit, is even more improvements to shader compilation. From the release notes it states the use of "pipeline libraries was extended to pipelines with tessellation or geometry shaders in order to further reduce stutter". On top of that, if your GPU driver supports it, more features of the VK_EXT_extended_dynamic_state3 extension are being used to reduce stutter when MSAA is on.
Another performance upgrade is that DXVK will use fewer threads for background optimization of graphics pipelines, which may make games smoother on some systems but it doesn't change the initial shader compiling.
Some other improvements include:
- A new GLFW backend for Native Linux builds using DXVK.
- More consistent D3D11 performance.
- A workaround for the Uplay overlay getting stuck on.
- Fixes for: Ashes of the Singularity, Battlefield: Bad Company 2, Cardfight!! Vanguard, Gujian 3, Resident Evil 4 HD, Saints Row: The Third, Sekiro: Shadows Die Twice, Sonic Frontiers and Supreme Commander: Forged Alliance.
I'm quite excited to see all the improvements. Hopefully it won't be too long before the Steam Deck and Proton together get upgraded to make use of it all.