 What do you think? Can you tell if RTX is on or off? Going through old posts from the launch of the RTX 2000 series is kind of like looking through a war zone. Many gamers and developers were excited about the new visual improvements and the ease of development that real-time ray tracing would bring to the table. Others, on the other hand, were outraged at the idea of paying a premium for a feature that they weren't asking for, especially if it seemingly came at the cost of performance in games that use rasterization, which at that time was all of them. But fast forward three years and there are about 50 commercially available games in Nvidia's RTX support list with more to come. Leaving only one question then. Can normal people even tell the difference anyway? Just like, can they tell the difference? Our sponsor. GlassWire. Keep track of the weird stuff that's connected to your PC even when you aren't using it. If a strange device joins your Wi-Fi, you'll be notified instantly. Get 25% off using code LINUS at the link down below. Our test setup is pretty straightforward. Jesse from our writing team set up two identical gaming PCs ahead of time so that even I won't know which one has RTX on and which one has RTX off. Our subjects get up to five minutes to experience each game and will be encouraged to just game as a normal gamer would. So they can switch back and forth between the two systems instantly using this KVM from Level One Techs, by the way. Those guys are awesome and they can do whatever they want as long as they don't enable performance metrics and don't manually check the settings in the menu because that's cheating. Can I watch the benchmark? Because there's a scene there at the start. No you can't because one is RTX. That right. One's going to perform way better. Bullsh**. Is he going to run a benchmark? Yeah you can't do that. I didn't want to look at the FPS. Once their time is up, they simply select which system they thought had RTX on and describe what they liked better about the RTX experience. I've never actually seen RTX Minecraft before. Where was the lava? Because I know it's supposed to be like extra pretty, right? Yes, it's actually like not that hard usually if you know what to look for. Say that in sentence one, Sam. You have this mic a bit closer to you. Oh sure, yeah. You're so soft-spoken. Sorry man. I know I'm so quiet and relaxed. I like it. Linus always scares me because he wants more energy. Man, that bird's got a really long tail. Say that again. Man, that bird's got a really long tail. While ray tracing is getting a ton of attention from gamers now, it's not a new idea by any means. The basic concept actually predates rasterization and in the 3D animation industry, it's been in use commercially for well over a decade. But the thing is, in order to determine what a scene should look like using real traced light rays, you need to emit a massive amount of them from a point or ambient light source, which will then bounce and diffuse around the scene enough times that they eventually become sort of negligible bounces and are no longer needed. Now, that sounds fine and obvious until you realize that you might need hundreds of thousands or millions of rays to even get a somewhat decent picture out of them. Many people don't realize that the simple fact that an image is ray traced does not mean that it will look good. Look at this quick blender render. See how noisy it looks as though a bunch of the detail is missing? When non-real-time ray tracing is calculated, the work is divided up into overlapping chunks called passes, and they are added on top of one another until a cleanly lit image is produced. This can take minutes or even hours for a single 4K frame though, and that's on modern hardware. So you can imagine why some new ideas were needed to make this technology viable for games where we need 60 frames per second or more. While there is a clear competitive disadvantage to using ray tracing in a fast-paced title like Fortnite, for example, where every frame matters, it's still impressive that NVIDIA's RT cores work as well as they do. In short, RT cores are designed to perform two tasks that are specific to path tracing, which is kind of a shortcut version of ray tracing. These are called bounding box tests and ray triangle intersection tests, and they save thousands of instructions per ray that would otherwise have to be done by the GPU's stream processors. And in the 3000 series, their second-gen RT cores are more powerful than the first-generation ones, meaning that we should see them continue to improve over time. Yeah, it seems like the shadows are just struggling more in this one. I don't know which one it is because last time I thought the one that looked better, in Wolfenstein, I thought the one that looked better was the rasterized one or the reflection mapped one. So maybe it's the same thing here where the shadows that looked better to me are actually the non-ray traced ones, the ones that we fake. So yeah, this is performing better, but it's not that big a deal, I guess. The problem is that it looks better, too. So, I mean, Minecraft beta is beta, right? So it's not like they can't add things later, but man, like that water, though, just looks so much better. Isn't it so gorgeous? It looks like water, whereas the water in Minecraft RTX kind of looks like ocean water all the time. Okay, wait a minute. If ray tracing is so accurate and therefore better, what was that? How could any test subject fail to tell the difference or worse, prefer the traditionally rendered method? Think of ray tracing as a final boss that's impossible to beat, because that's what it was for years. What's a gamer to do, right? Gee, now, obviously, we're talking game developers, so I don't mean getting a subscription to GamePro Magazine here, but rather I mean building techniques of clever tricks that allow you to fake realistic rendering. These altogether have come to be known as rasterization. Raster rendering means that a lot of the lighting, shadows, reflections, and other visual elements are baked into the level geometry and handled with packages of processing and effects on a per-pixel level. These are called shaders. Over the years, these techniques have become more complex and refined, allowing things like dynamic shadows in real time by using clever projection mapping, as well as tricks like more advanced dynamic reflection mapping. But the core idea of tricking the player into thinking that the lighting is being handled in real time has remained the same throughout all of these innovations. God, this is really hard to tell the difference. And I don't really feel like there's a huge performance drop. What GPU are we using? 3080 or 3090? So I'm right now creating a harsh shadow, a pretty direct reflection of the sun here on the water. And let's switch back to system number one. They look pretty similar. I don't really spot a difference right now. As you can see, these cheats or tricks that game developers use have become so good that they're kind of an obstacle to real-time ray tracing catching on, even though that final boss is actually beatable. Reflection maps are an excellent example of this fake it till you make it approach. They're essentially a 360-degree view of the current scene that's been remapped and projected onto an object or surface. Then with the right amount of distortion and selective color removal, as well as dynamically swapping out or changing the map as you move around, you can get high performance, visually appealing, and quite convincing reflections. Some really good examples of this are games like Dirt 3 and Need for Speed Hot Pursuit. It's not perfect, of course, and in games like CS GO, it's actually very obvious that your scope reflections, for example, don't really match the environment. But in the heat of a clutch round, it's not something that you're likely to notice, and certainly is a lot better than giving up so many FPS, leading us finally to the results we've been teasing. Okay, so for Shadow of the Tomb Raider, I believe number two has RTX on. What the f***? What? What do you mean? I had a feeling I'm like, it's like I'm watching like a scientist at work like analyzing, what is it? Okay, so the thing that tipped me off the most is that the shadows in the center of the screen here for this tree are shimmering as they're moving on the machine with no RTX. That indicates to me that that's a shadow map, whereas the RTX machine, it's kind of sort of shimmery, but it's not quite as bad, and also the shadows are a little bit softer and they tend to, they start sharp and then they go soft, whereas the shadow map is consistently soft. You are 100% correct. Okay, as expected then, our most technical staff had no trouble identifying both the benefits and drawbacks of real-time ray tracing. But mathematically speaking, most people aren't Anthony, so what about them? Okay, this might be a pretty good spot. If I'm facing the sun, which is like right there, I can see reflection on the water here and also on the rock here. And let's go back to system number two. Wow, they look pretty similar. Oh my God. Yeah. I think for number two, it looks better. It's like glowier. The lava specifically, there's this effect around it. Yeah, whereas like for number four, I feel like everything's a bit flatter. There isn't as much detail to the lights and stuff like that. It's just like a general, like this block has lava, so then the other one should have it around too, right? I don't know, I could be totally wrong. I think this one, number two, is ray tracing on. And what makes you think that? The sharpness of the reflections in the water. It looks a little more reflective than in the other one. And also the shadows, because they're softer, I feel like that's how leaves would actually look in real life. It would be a softer shadow because they're all together. You wouldn't get these crisp jagged edges. But now that I say that, like I'm wondering if the light's shining so hard through it that it's creating those jagged edges with RTX on. I don't really spot a huge difference, but my God telling me system number one is the one with ray tracing. So this one is the one with ray tracing. Although we saw varying levels of success with the number of games each person got right, and which game specifically they got right, the overall trend from our test is pretty simple. The people with any knowledge of 3D rendering, and especially with firsthand experience gaming on RTX at home, were way more likely to nail it. As for everyone else, telling the difference actually isn't easy. The truth of the matter is that with current titles that support ray tracing, it's pretty difficult to tell whether it's on or off without pixel peeping. More on that in a moment. Even when we did prompt people to look closer, it was extremely challenging and the results were quite similar. And for fun, we threw an extra scenario at some of our participants where we had the exact same game running without RTX in both cases to see if they could find the difference. Are they both off? Oh, oh yeah, okay. I was like they, yeah, I could not tell the difference really. I guess I was trying to find a difference, but there was none. Okay. They couldn't, but they also weren't a hundred percent sure. So as it turns out, if a game already looks really good with rasterization, our brain will in some cases see things that are not necessarily there. And this happened to some of our participants in Wolfenstein, for example. They would notice parts of the lighting that looked, you know, better in this one when the only difference in that game was actually in the reflections. Bottom line then, is Nvidia selling snake oil with RTX? Absolutely not. What kind of question is that? I mean, in games like Minecraft for Windows 10 and the upcoming Metro Exodus Enhanced Edition, it is clear how much of a difference it can make to the atmosphere of a game. And in the long term, ray tracing is a huge boon to game developers as well. Because it behaves more like how real light does, it can save a ton of time that would have otherwise been spent setting thousands of super hacky parameters to get a scene to look convincing. But the tech is still in a relatively early state, but it will be the future. I mean, just think about it. Add in your light sources, set your diffusion, refraction and reflection parameters for every surface and bam, you're done. Kind of. It's a bit more complicated than that. And if you want a more detailed explanation, we do have an episode over on TechWiki that goes into more detail. But with all of that said, it's clear from our experiment today that in the right hands, rasterization is still a potent tool and this industry transition is going to take many years to complete. So maybe don't feel too bad if you still haven't managed to get your hands on a newfangled RTX GPU. You know what you should get your hands on though? Your own website. Making a website doesn't have to be hard. 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