For the past several generations, Nvidia has released a tech demo alongside a new generation of graphics cards. It's always a remaster of a classic game bathed in ray-traced lighting, usually to the detriment of the atmosphere and vision of the original release. Half-Life 2 RTX is something different.

If you own the original game, you can download a free two-hour demo for Half-Life 2 RTX now. The full game is still in development. Although the demo serves to show off Nvidia's latest features, it also shows off the tech that could dominate the next era of PC gaming. It's an exciting future, no doubt, but it's one that largely locks out budget and non-Nvidia users.

Half-Life 2 RTX shows off true neural rendering

It's much more than a lighting makeover

Half-Life 2 RTX may look like another classic game with a swipe of ray-traced lighting slapped on top, but it's more than that. Yes, you're getting full-on path tracing, and with adjustments for the minimum and maximum number of light bounces. But more importantly, Half-Life 2 RTX serves as a showcase for all of Nvidia's technologies, and the start of neural shaders in games.

There are three main enhancements Half-Life 2 RTX has. It has path tracing, enhanced meshes, materials, and lighting, and the first neural shader we've seen, which Nvidia calls Neural Radiance Cache. Neural Radiance Cache is the most interesting place to start. As the name implies, it's a cache built specifically for ray-traced indirect light. Rather than letting light bounces go to waste, the shader leverages neural networks to infer light bounces, which is stores in a cache.

Above, you can see Neural Radiance Cache in action. Half-Life 2 RTX doesn't allow you to turn this feature off, so I'm comparing the lowest preset (Medium) to the highest (Ultra). The difference is small, but the small patches of grass I've highlighted show off what the shader is doing. You can see on the Ultra preset these complex shadows forming in the patches of grass, which are completely absent from the Medium preset.

For a clearer comparison, see the video from Nvidia above.

Neural Radiance Cache is only one piece of the puzzle here, though. It wouldn't work if the light didn't have materials to interact with, and that's where Half-Life 2 RTX shows off major improvements over the original. You can see in the comparison above the immediate difference there is in the quality of the game with the new assets. It's not just a couple of upgraded textures, either; the meshes are more complex, the lighting is moodier, and the materials are physically-based to interact with the path-traced lighting.

It's staggering how big of a difference these new assets make in some cases. In the scene above, the difference in quality for the Gravity Gun is immediately apparent, but there's more going on here. If you look at the catwalk toward the back of the scene, the grating isn't even rendered at this angle with the original assets. It looks like there's no floor at all, whereas with the enhanced assets, the grating is there and interacting with the light accurately.

This is where Half-Life 2 RTX really shines. Although Nvidia talks up the advantages of ray-traced lighting -- I mean, RTX is literally in the name -- that's actually the least interesting part of this game. As you can see in the comparison above, the difference between the Ultra and Low lighting presets isn't nearly as big as the difference between the original and enhanced assets. The most immediate difference is the lack of volumetrics.

There are scenes where the ray-traced lighting makes a difference, particularly in a moody area like Ravenholm where the Half-Life 2 RTX demo is set. But if you need to reduce the quality of the lighting, I'd certainly do that before turning the enhanced assets off.

DLSS is required on just about anything

You won't get away with native performance

Half-Life 2 RTX looks amazing, and your PC is going to let you know that fact immediately. This is one of the most demanding games I've ever tested, which is not dissimilar from Portal RTX that we saw a few years back. It's not just the lighting that pushes the envelope, either. VRAM consumption does, too.

On an RTX 5090, I clocked Half-Life 2 RTX gulping down 24GB of memory at 4K with the Ultra preset and DLSS disabled. I've never seen a game climb that high before, and it makes sense. This game is releasing exclusively on PC after all. Part of the reason the game consumes so much is that it features RTX IO and an enhanced texture streaming system. If you have the VRAM to spare -- and the RTX 5090 certainly does -- the game will take as much as it needs.

That shouldn't be something you need to worry about regardless. Turning on DLSS reduces the consumption down to just over 8GB at 4K, and DLSS is required to get anywhere near playable performance. You can see that with my testing above. Even the RTX 5090 couldn't muster 30 fps at 4K without DLSS. You need DLSS Super Resolution to even cross the 60 fps mark, along with some help from Multi-Frame Generation to get into the triple digits.

DLSS is the real difference-maker here, too. I tested the different quality presets for the lighting, along with turning the enhanced materials off, and that barely moves the performance needle. Even in the best-case scenario with the Low lighting preset and the enhanced assets turned off, I wasn't even able to cross 50 fps.

Unfortunately, DLSS is really your only option. Nvidia includes its own Nvidia Image Scaling (NIS) and TAAU, both of which offer mediocre image quality. Unsurprisingly, there isn't FSR 3 support, though I suspect modders will quickly add it to the game. Lossless Scaling is another option if you don't have access to an RTX GPU, but I don't have high hopes for raw path-tracing performance on anything other than Nvidia's last couple of generations.

The Half-Life 2 remake you've been waiting for

This is bigger than a tech demo

Nvidia has dabbled with these remasters for the past several generations. It started with Quake 2 RTX before moving onto Portal with RTX. Now, we have the demo for Half-Life 2 RTX, which will include the full game once it's released. And for the first time, it feels like a proper game rather than a tech demo.

Make no mistake, this is still a showcase for Nvidia features, and I don't think anyone running non-Nvidia hardware will have much luck in the performance department. But playing through the two-hour demo of Half-Life 2 RTX felt like playing Half-Life 2. After a while, I stopped thinking about the reflections and materials, and I started getting immersed in one of the best video games ever made. What stood out most was how much atmosphere Valve was able to create with how few visual flourishes it had at the time. That atmosphere is still present, which isn't surprising considering this project doesn't come from Nvidia directly. Half-Life 2 RTX is made by Orbifold Studios, which is made up of developers who've worked on several Half-Life mods.

From a technical standpoint, Half-Life 2 RTX serves to show the best and worst of what PC games could look like in the future. It looks amazing, and you get unbelievable performance with DLSS running at full tilt. But it's a future Nvidia has built for itself. AMD and Intel users are largely locked out of experiencing the game, and the obscene VRAM consumption puts a damper on lower-end GPUs like the RTX 4060.

There isn't a release date for Half-Life 2 RTX yet, but if you own the original game, you can download the demo for free on Steam now. Given how meaty the demo is, I hope we'll have more news on the full release some time this year.