DX-Ball 2: 20th Anniversary Edition (922400) poor performance

Compatibility Report

• DX-Ball 2: 20th Anniversary Edition
• 922400

System Information

• GPU: RX 560
• Driver/LLVM version: Mesa 20.0.0-rc1/ACO (mesa-aco-git from Valve testing repo)
• Kernel version: 5.5.7
• Link to full system information report: https://gist.github.com/parkerlreed/521703ff485195c364a3ec2d1b2669f1
• Proton version: 5.0-3 (Also tested with the officially supported 3.16 with the same result)

I confirm:

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

steam-922400.log

Symptoms

The entire game appears to lag. Just starting it up, the menu is choppy and this persists for the entire session.

Tried with and without aco (RADV_PERFTEST=llvm) and also using Wine's D3D implementation. Always the same result.

Reproduction

Install game and try launching either via 3.16 officially supported or 5.0.

Start by reviewing steam-922400.log alongside the compatibility report and full system information report. Reproduce the choppy menu and session using Proton 5.0-3 and the officially supported 3.16, with and without ACO and Wine's D3D implementation. Done means identifying and resolving the cause of the persistent lag, with performance confirmed during a full session.