Conclusion

NVIDIA has been teaming up with game developers of legendary older titles to bring ray tracing to these gems. Previously we've seen ray tracing integrations for Quake II, Minecraft, and Metro Exodus, on Thursday this week Valve will release Portal with RTX, we've had the chance to check out a beta build. You have probably heard of Portal before, it's a first-person puzzle game that sounds too simple to be amazing. You have a gun that can create wormholes between two walls, so you can traverse the map. With 98% positive reviews out of almost 100,000, Valve's Portal is one of the highest rated games ever on Steam, and rightfully so. Despite the dated graphics the game is awesome to play and tons of fun—you should try it.

The new Portal RTX has received the full arsenal of NVIDIA technologies. It comes with ray tracing, DLSS, DLSS frame generation (DLSS 3), and also new features such as Shader Reordering, Opacity Micromaps, RTXDI, an improved denoiser, and many more. If you take a look at our comparison screenshots it becomes apparent what a monumental improvement the new version of the game is. Especially lighting looks incredible now. While in the original Portal you could easily spot incorrect and unrealistic lighting and shadows, things look completely different in the RTX version. Everything looks perfect and physically accurate. I did play through the game, trying to find issues and there are indeed some locations where things don't look right—if you spend time thinking about how "correct" results should look like. This is nothing you'd ever notice during normal gameplay, and I feel it's certainly within the boundaries of what game artists are allowed to do to make things look slightly different for effect.

As expected, the performance hit from ray tracing is massive. The original Portal runs at around 245 FPS in any resolution on our test system, no matter the graphics card, it's purely CPU-limited. With RTX enabled, framerates drop considerably. Even the mighty RTX 3090 Ti only gets 49 FPS at 1080p (!!). NVIDIA's new Ada GPUs do better here, RTX 4080 gets 67 FPS and RTX 4090 reaches 93 FPS. Remember, that's at 1080p. Once you dial up the resolution, FPS go down even more. At 1440p, the 3090 Ti gives you 28 FPS, 4080: 39 FPS and 4090 manages slightly below 60, with 56 FPS. At 4K, everything ends up below 20 frames per second, only the 4090 is able to reach 26 FPS. These numbers are hardly "playable" by PCMasterrace standards, that's why it's essential that you use DLSS to cushion the render load. With DLSS enabled, things are looking much better and Portal is extremely playable. Still, even with DLSS, the requirements are high. For example RTX 3070 with DLSS Balanced at 1080p is barely able to break the 60 FPS barrier. The AMD Radeon RX 6900 XT really isn't fit for this level of ray tracing. It starts out with 5 FPS at 1080p and almost runs in "seconds per frame" mode at 4K.

During testing I was surprised that several "decent" cards like RTX 3080 and RTX 3070 ended up with just a single frame-per-second at 4K. Digging down further it turns out the VRAM requirements of Portal RTX are really high. We plopped in a 24 GB RTX 4090 and tested various resolutions. At the outdated resolution of 1600x900, the VRAM usage already hits 7.5 GB. At 1080p you need 8 GB VRAM, at 1440p you better have 10 GB, and at 4K the game allocates over 16 GB memory—a new record. Somehow I suspect that the game isn't really optimized for VRAM usage, but this goes to show that future games could end up with serious memory requirements. Enabling DLSS will drastically reduce memory usage though, because it dials down the rendering resolution, so that's always an option.

Overall I have to say I'm very pleased and impressed with how Portal turned out visually. It's also great to see how NVIDIA's various innovations in the RT space come together to unlock additional performance and stunning visuals. On the other hand, the high hardware requirements make it a tough pill to swallow. Portal has been a huge success even with outdated graphics, just like many other titles from Valve. Games are played because they provide entertainment through game mechanics—challenging puzzles in this case. No doubt, stunning and realistic graphics are a big deal in the gaming industry, but I have to wonder.. is it worth spending $1000+ on a graphics card just to play Portal? Is the gaming experience really that much better? That's an answer only you can give.