One-fifth of the framerate when enabling RTX and TBH, I'm not impressed from the two screenshots.
In the first screenshot, the RTX version seems to be lacking a lot of shadow definition, even in areas where the energy ball isn't throwing light. I was expecting ambient occlusion and it appears to be absent. Finally, the materials seem wrong. The shiny metal piston to the left no longer resembles a shiny metal piston, that's clearly supposed to be polished steel with a thin film of oil on it.
In the second screenshot the main differences appear to be shadows behind the piping, dynamic shadows from the ceiling vent, and volumetric fog further away in the scene, all of which can be easily and cheaply added without RTX, but are simply lacking in the original because Valve never included them 15 years ago. The current iteration of the Source engine can handle these effects easily, as demonstrated by Black Mesa, which itself dates back almost as far as the original Portal.
In both cases, the RTX version looks wrong, and the biggest difference by a country mile is that the textures were changed which has nothing to do with raytracing. I'm sure it'll look better in motion but for what seems to be very little visual improvement, that drop from 300fps to 60fps is one of the worst, least-efficient RTX implementations to date. If anything, it simply serves to demonstrate how woefully inadequate modern RTX cards are for DXR effects in more demanding games.
