System Information
Operating system: Linux-5.14.15-arch1-1-x86_64-with-glibc2.33 64 Bits
Graphics card: NVIDIA GeForce RTX 2070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 495.44

Blender Version
Broken: version: 3.1.0 Alpha, branch: master, commit date: 2021-11-02 08:57, hash: rB223f2b27d1d1
Worked: 2.93.5

Short description of error
Enabling Optix denoiser renders artifacts across entire viewport or final render image.

Exact steps for others to reproduce the error

1. Switch to Cycles render engine
2. Set viewport to rendered view
3. Enable Optix viewport denoising
4. Image should be strange and pretty.

I suspect this is a problem with the Nvidia driver which was updated on the 31st.
I tested one of your archived builds from October 23rd (blender-3.0.0-alpha+master.231d66d8ba35-linux.x86_64-release.tar.xz) and it was broken as well.
And I think I would have noticed it in that time frame if it was solely a problem with Blender and not the driver.