Dirt 5 on Xbox Series X – what’s the difference between 60fps and 120fps?.
What makes the difference in the new generation? Today the embargo ended on our first look at a true Xbox Series X title – Dirt 5, from Codemasters studio in Cheshire. Xbox Series consoles benefit from three game modes, including the ability to play at 120 photograms per second on compatible screens – first impressions are highly favorable. What we are seeing today is not the final version and there are optimizations that took place until the launch on November 10th, but the producers seem determined to deliver an engaging and fun driving game that gives the user a lot of choice in the generational leap of the power of the CPU and GPU.
Dirt 5 sits on an extraordinary basis, using an evolved form of the Onrush engine developed by Codemasters Cheshire, in which many of the employees originally worked at Sony’s excellent MotorStorm and Driveclub franchises. Onrush was not the commercial success that many expected, but the technology is first class and has been further improved in Dirt 5. The result is a highly flexible and dynamic engine that hits a lot of high technology things: we have materials captured with photogrammetry , mud and snow deformation, dynamic weather, volumetric fog – and a base target of 60 frames per second on next generation consoles.
The best technological features of Onrush are adapted for an arcade-style rally game, but it goes further in several aspects. Vehicles are wider and more geometrically complex. Physics has been rewritten since Onrush, although track details have gone up even further. The engine is also more scalable, taking into account the machines of the current generation but also the Series S, X and the PC. It even includes a split-screen mode for four players, something that we rarely see in racing games these days.
The first thing that strikes you about Dirt 5 is its terrain. From the gravel of a trail on an Italian mountain to the reflective muddy tracks in China, all locations have a unique look, where the materials have an impact on the physics of the game. Most of this is best seen on the bumper camera: protruding stones and tire tracks in the snow are particular highlights. Onrush’s workflow relied on captured drone photogrammetry to create an initial mix for the environment – an approach that is likely to be repeated here. The result gives Dirt 5 physically correct materials that react to light consistently. This is crucial; a day-night cycle, as well as dynamic weather, often transform the track at the end of a race. Puddles even form in terror as the rain settles. The light is in constant flux and then all materials have to adapt realistically – Dirt 5 gets it right.
The effects and physics are also impressive. Dirt and procedural damage are a big part of adding immersion to the run. The mud is sprayed and the dust lifts behind your competition’s tires. All the debris lifted is accumulated in the body of the cars, which then deform and dent on impact. All told, it is an impressive sight on the starting grid – 12 cars can create absolute chaos on mud tracks. Much of the physics engine is built at home – for tires and suspension – not to mention the impact these vehicles leave on the track itself. Tire tracks accumulate on icy circuits, while snow deforms realistically using a geometric model to simulate volume. Again, everything looks a lot more dynamic than in previous Dirt games, and it can change over time.
This brings us to the performance of the game, at least in this non-final version of the code. The good news is that the choice is yours how you want the experience. We have three game modes in the Series X: one for framerate, one for image quality, and finally 120Hz. The final metrics have not yet been agreed and may improve when the game is released, but at this point, the framerate mode runs at 3840×2160 dynamic, aiming for 60fps. Visually speaking, the game does a good job of staying in 4K; the selection of cars, the opening screens, and the action after separating from the group – all in 4K. The only drop in resolution is on the initial grid, to 3328×1872 – but that’s it.
All three Xbox Series X modes compared. Image quality and framerate modes run at 4K dynamic, while 120Hz mode is at 1440p dynamic – scaled here to 1080p.Central mechanics like physics are translated equally between the three modes – as well as textures. However, there is a notable boost in the texture filter in the image quality mode (notice the floor on the right).Viewer density is adjusted across all modes to suit high performance. At 120Hz, viewers disappear. Likewise, the quality of the shadows regresses, while the image quality mode leads the three options.To reach 120Hz, the geometry of the LOD was adjusted – most notably on the precipices in front of the car.All three versions look incredible on the go, with the help of an anti-aliasing storm. Even the 1440p used in 120Hz mode is well on the move, due to the duplicated pixel effect produced by Series X by the second.The landscapes of Dirt 5 are varied and beautifully presented regardless of the choice of mode. It’s good to have so many options.
The image quality mode also runs at dynamic 4K with a 60fps target, but the difference is that the focus is not on improving the resolution, but rather on the game’s settings. Among the differences we see are higher quality shadows, better texture filters and an improved level of crowds around the circuits. There are possibly more factors to take into account – such as the geometry of the LOD (Level of Detail) – but the most obvious improvement is in the shadows. In terms of resolution, the image quality mode hits natively at 3840×2160. However, if you are in the middle of 12 cars, there is a drop in resolution to 1800p at the lowest level. Again, this is the extreme and may well change in the final code.
The good news is that performance looks good, even in a non-final state. Both the image quality and framerate modes are mostly locked at 60fps once you are out of competition, and when the framerate lowers, there are some screen tears. The framerate mode is obviously more consistent, while the image quality mode does its name justice. It does not give the same priority to performance, so more and more falls from far to far and at the moment the balance is positive for both modes.
Perhaps the most exciting thing about the Series X is the 120Hz mode, which is only visible if the console has this refresh rate selected. If you are using an HDMI 2.1 screen, you can keep the 4K signal, but existing HDMI 2.0 screens require you to lower the resolution to 1080p or 1440p, depending on the specification. At this point, it is worth mentioning that the Xbox Series X will continue to render the same resolution internally as if you were connected to a 4K screen. The screen controller will simply shrink the image before sending it to your screen – so on my LG B8 OLED, I can select 120Hz mode and play Dirt 5 at 120fps, but any rendered internal resolution will be reduced to 1080p – the technical limit of my screen.
In the current situation, the 120Hz mode inevitably reduces settings to free up space on the GPU for extra temporal resolution. Doubling the framerate from 60fps is no small feat, requiring a frame every 8.3ms instead of 16.7ms. All the central physics and logic of the game translate intact from the normal options, so it is on the GPU side that we see change. The viewer count is further reduced, as well as the quality of the shadows. However, the biggest change is that it renders the dynamic 2560×1440. In other words, it maximizes the old HDMI 2.0 specification in terms of what the bandwidth can show – 1440p 120Hz at the peak. Falls are possible, to 1080p at least right on the starting grid, then adjust to other numbers in the middle.
The benefit of doubling the refresh rate from 60fps is evident in a racing game. When every millisecond counts, for every touch on the analog, having a lower latency response on the screen is a great benefit. There is no doubt that the jump from 30fps to 60fps is more essential, but I suspect that 120fps is seen as the purists’ choice. It’s the icing on the cake and new territory for consoles. For me, the horizontal movement of the camera in the curves best demonstrates the visual effect; a continuous slide not possible at 60fps. It may not be necessary for all games, but shooting and racing games clearly reap the best benefits when on the move.
Performance is not perfect, but it is very close to 120fps. Interestingly, there are a few crashes at times, the usual culprit being the starting grid – but it is not a major nuisance in practice. I saw a drop to 90fps, but at such a high refresh rate it is difficult to distinguish by eye, especially if you are using a screen with variable refresh rate technology. Once we break the 60 fps barrier, the notion of fps as a metric to describe the experience is debatable. Consider this: there is a space of 30fps between 90fps and 120fps, but the variation in frame time is only 2.8ms – compared to 16.7 ms from 30fps to 60fps. The basic conclusion: framerate drops below 120fps have less impact on the experience, especially when they are fleeting.
All of this just touches the surface of Dirt 5’s ambition. As a multiplatform launch – on four Xbox machines, three PlayStation and a multitude of PC configurations, there’s a lot to cover. For now, I’m glad to see the three modes of the Series X, all of which approve of the power of the new generation in different ways. What is also a relief is that, regardless of the mode you use, Dirt 5 is an impressive leap for the series and should accompany the launch of new generation consoles in style.