The Portal 2 RTX Remix path tracing mod looks incredible, but its improvements come at a very high cost, as path tracing in the game is so demanding that it utterly destroys performance at 4K resolution on an RTX 4080 GPU.
A new comparison put together by MxBenchmarkPC does a great job highlighting how demanding path tracing can be. At native 4K resolution, the framerate drops from around 200 and 300+ FPS to the low 20s and 30s range, depending on the scenario, on an RTX 4080 GPU, which should be more than capable of delivering higher framerates even with path tracing.
For playable framerates, Portal 2 RTX Remix essentially requires NVIDIA DLSS and Frame Generation to push past the 60 FPS range at 1440p and 1080p resolutions in some scenarios. Related Story Red Dead Redemption New Mods Introduce Historical Overhaul of Weapons, Upscaled Textures For Different Objects, First Person View ModeIf you want to try out the Portal 2 RTX Remix mod yourself, you can download it by going here.
The mod was never intended to support the game, and the game effects are rendered using shaders, so you should expect to experience some other issues besides the low performance.
Portal 2 is the second entry in the series created by Valve, introducing a variety of improvements over its predecessor, including a separate two-player cooperative campaign.