As Linux is my primary daily driver, I try to stay in it when gaming most of the time. I decided to dust off some of my older games that I never completed. One such game is Deus Ex: Mankind Divided, which coincidentally, was a divisive game among the gaming mankind, receiving mixed reviews.
Anyway, this is one of the games that Feral Interactive ported to Linux in their heyday when companies like Square Enix were porting a lot of games to Linux for the ill-fated Steam Machines. Thankfully, even after Steam Machines failed, some game companies continued to port to Linux. Feral uses its own proprietary translation layer rather than WINE, and it generally works pretty well. But back when they ported DXMD, Vulkan was in its infancy.
As a result, this game was ported to Linux to run on OpenGL, which means it's horribly CPU bound and does not come close to matching Windows performance. When I remembered this, I immediately switched to Proton.
The game starts with Proton Experimental without any problems, but for some reason, my trusty Steam Controller would not work even though the game clearly detected it. I can only guess that this was some sort of glitch because it eventually worked but only after a full reboot.
Performance wise, the game runs well, keeping in mind that I have an RTX 3080, which is grossly overpowered for a game from 2016. Having said that, with the game on Ultra textures, it uses 9.5 GB of VRAM, which is uncomfortably close to my graphics card's 10 GB maximum. Ultra textures also slow down the FPS, which is unusual for a game. After some quick Googling, I found that this was a common problem with this game. The Ultra textures are clearly not well optimized and gave people all kinds of problems back in 2016. I lowered them to Very High, and it was smooth sailing without noticeable degraded visual quality at 1440-ultrawide.
Finally, it is worth noting that I have chosen to use VKD3D to run the game's DirectX 12 version rather than DX11. In general DX12 versions should be preferred when using proton, as Valve's developer showcase for the Steamdeck even confirmed. With it you usually do not have to worry about shader compiling and the accompanying stutters that come with DX11. And, of course, most games being released in 2022 use DX12 by default or even exclusively.