Portal RTX became the Ultimate GPU Flex — but only if you’re packing serious power

Lightspeed Studios dropped a monster update for Portal RTX, adding DLSS 4 with multi-frame generation (MFG) and NVIDIA’s new RTX Neural Radiance Cache (NRC). The patch is designed to make the game more playable at 4K with full path tracing enabled, which was borderline impossible before unless you enjoy watching a slideshow.

Let’s be clear: Portal RTX is one of the most punishing games on PC right now. With all effects maxed out, it runs at 20 FPS on an RTX 5090 at native 4K. Yes, the most powerful GPU on the planet barely holds it together. That’s how wild this tech demo has become.

"It’s THAT brutal."

But this patch changes the equation. DLSS 4, built on a new Transformer-based AI model, adds Performance Mode and lets you multiply framerates with MFG. You can now generate up to three extra frames per actual rendered frame. That’s how RTX 50-series users can finally push the game past 60 FPS.

Sure, using MFG X3 or X4 can cause some input latency, but that’s the price you pay for beauty in this beast of a game. For many, it’s worth it.

DLSS 4: Big Boost, Big Expectations

DLSS 4 does more than just frame generation. With the transformer model, Ray Reconstruction and DLAA (Deep Learning Anti-Aliasing) also get a quality bump. The visual improvements are sharper details, fewer artefacts, and less ghosting during motion. These upgrades apply even if you’re not using frame gen, so every RTX user benefits.

To use DLAA, just head into the advanced graphics menu and select “Full Resolution” under DLSS mode. That activates DLAA without any upscaling.

For RTX 50-series users, the full DLSS 4 feature stack becomes available. Expect huge framerate improvements, especially when combining Performance Mode with MFG. The boost doesn’t come free—you’ll still need a beast of a card—but it’s now possible to enjoy smooth 4K path-traced Portal RTX without dropping to sub-30 hell.

Then there’s the RTX Neural Radiance Cache, a fancy name for a neural network-powered shader that drastically improves indirect lighting. NRC works by estimating bounced light more efficiently, reducing the load on the path tracer while making the lighting feel more realistic.

You can choose different quality levels for NRC, depending on your PC’s capabilities. Want max realism? Crank it up. Need better performance? Drop it to a lower preset. The setting lives under the “indirect illumination” options in the graphics menu.

This is one of the first games to implement NRC in real-time gameplay, and the visual gains are obvious. Light behaves more naturally in scenes, shadows are cleaner, and reflections stay consistent without turning your GPU into a jet engine.

Texture Streaming, Shader Fixes & Better Denoising

The update also improves how Portal RTX handles textures. There’s a new streaming system that makes smarter use of VRAM, keeping texture quality high without blowing past your memory limits. This is crucial for RTX 40 and 50-series cards that can get swamped at 4K with ray tracing on.

Shader compilation has been optimized too. That means less stuttering during gameplay and faster load times when booting into a new level. There’s even an on-screen notification now when shaders are actively compiling, so you know what’s going on if performance dips for a second.

The NVIDIA Real-time Denoising (NRD) library was updated to version 4.13, improving the clarity and stability of ray-traced shadows and lighting. The result? Sharper visuals with less flicker and fewer artefacts when the camera moves.

If you already own Portal RTX, Steam will auto-download this patch the next time you launch the client. If you’ve been sitting on the fence waiting for better performance, this update makes the game much more playable, at least if you’ve got the hardware to back it up.

This patch isn’t a magic bullet for mid-range cards, though. You’ll still struggle at native 4K on anything below an RTX 4080, even with DLSS. But for those with RTX 50-series cards, Portal RTX is finally starting to live up to its promise: a brutally demanding tech showcase that also happens to be one of the most iconic puzzle games ever made.

DLSS 4 and Neural Radiance Cache bring massive upgrades to Portal RTX, pushing the visual bar even higher while finally making it more playable—if you’ve got the rig for it.