I am running Linux Mint/Cinnamon v21.2 on an ASUS TUF A16 2023 Edition Laptop (FA617NS). The laptop has:

• Ryzen7 7735HS CPU (has i-GPU)
• RX 7600S d-GPU
• 32GB RAM
• 2x 2TB M.2 SSD
• 1920x1200 165hz display
• USB4, displayport over USB-C, HDMI
• Gigabit Ether, WI-FI 6

When I launch Steam it loads on the i-GPU. I installed Middle Earth: Shadow of Mordor using the Linux native option (not Proton) which uses Vulkan for rendering. It was suggested that I use the following launcher string (without quotes) in the Steam properties for the game: "DRI_PRIME=1 %command%". The game has an internal benchmark. In the game’s video settings the d-GPU is recognized as “Rembrandt” which is the same label shown in the inix report (inxi -Fx). However, when I run the benchmark it gives between 1 and 3 FPS. If I remove the launcher string from the Steam properties of the game, launch the game, and run the benchmark, the performance is so bad that it doesn’t render the benchmark.

The odd thing is that if I switch the game from Linux native to use Proton Experimental. The launcher string has no effect. I can run the game and its benchmark with Ultra settings and get between 140 and 150 FPS.

Does anyone understand what I’m doing wrong? How do I run games (especially Linux native/Vulkan) properly on the d-GPU without causing bad performance.