@kisak-valve
Using "PROTON_USE_WINED3D=1" fixed the stuttering dramatically, and made it playable.

D3D WITH VSYNC DISBALED LOG:
steam-8140D3DNOVS.log

@iWeaker4you
Enabling VSync, along with using WineD3D, made the game run perfect. Enabling VSync completely eliminated any stutters and freezes.

D3D WITH VSYNC ENABLED LOG:
steam-8140D3DVS.log

Using DXVK with VSync enabled was still producing stutters and freezing. DXVK behaved the same, whether VSync was enabled or disabled.

VULKAN WITH VSYNC ENABLED:
steam-8140.log

Compatibility Report

• Name of the game with compatibility issues: Tomb Raider: Underworld
• Steam AppID of the game: 8140

System Information

• GPU: 5700XT
• Driver/LLVM version: Mesa 20.3.4/11.0.1
• Kernel version: 5.10.0-14-generic
• Link to full system information report as Gist: https://gist.github.com/acdcfanbill/036425e800a2f51aca579b145876b1e5
• Proton version: Proton: 1603141982 proton-5.0-10b (from log)

I confirm:

• [x] that I haven't found an existing compatibility report for this game.
• [X] that I have checked whether there are updates for my system available.

launch log file

steam-8140.log.gz

Symptoms

Game fails to launch. There is no window that pops up or anything, just silently fails to start after several seconds. I tried various version of proton to run it and I've added PROTON_USE_WINED3D=1 to my launch options. I suspect it may be hardware (or drivers for this particular hardware) related as my hardware has failed to launch the game on every Ubuntu release since 19.10 up to my current install of the 21.04 beta. There has been no hardware changes, but several software updates including various kernels and mesa builds in each major Ubuntu version.

Reproduction

1. set Launch Options and Proton version if desired
2. click Play button
3. steam shows game as running for a few seconds then it shows it as not running

I was thinking about this issue and decided to test something as the previous person with an issue also had a 3950x processor but an NVIDIA GPU. It might have to do with the number of CPUs the game sees/launches on? I've just adjusted my launch options to this PROTON_USE_WINED3D=1 taskset -c 0-3 %command% and now the game starts and runs very smoothly. The game must not handle 16 cores/32 threads very well because I can adjust the taskset command from -c 0-1 all the way up to 0-30 and it works, but if i pass it all 32 threads with -c 0-31 it fails to start the game again.

I was thinking about this issue and decided to test something as the previous person with an issue also had a 3950x processor but an NVIDIA GPU. It might have to do with the number of CPUs the game sees/launches on? I've just adjusted my launch options to this PROTON_USE_WINED3D=1 taskset -c 0-3 %command% and now the game starts and runs very smoothly. The game must not handle 16 cores/32 threads very well because I can adjust the taskset command from -c 0-1 all the way up to 0-30 and it works, but if i pass it all 32 threads with -c 0-31 it fails to start the game again.

That's interesting... Yes, I can confirm that this is actually the behavior, in fact after knowing about this, I searched and found another post with similar problem in the steam discussion of the game https://steamcommunity.com/app/8140/discussions/0/2791621786941084149/, so indeed this doesn't look like a problem of proton