Why Modern Games Need More Disk Space and Speed Than Ever Before
By: Christian Behler
Tags: Gaming, Features, Hard Drive, Games, Game Development

Why Modern Games Need More Disk Space and Speed Than Ever Before

Games are placing increasing demands on storage mediums

If you have downloaded a modern game recently, you may have noticed that the disk space requirements have increased dramatically over the past few years. In addition to just the raw storage capacity, the speed of the device is also becoming a lot more important. Just a few years ago, a normal hard drive was sufficient for almost every game. SSDs were new and expensive and if at all, regular consumers only had a small SSD for the operating system. And while SSDs have gotten a lot cheaper since then, they are still more expensive than HDDs, which means you can have fewer games on your device than you could have a few years ago. Given the importance of storage for modern games, it’s not surprising that a major focus of the PS5 announcement stream was the SSD, which is supposed to be up to 100 times faster than the PS4 HDD.

Photo by Denny Müller on Unsplash.

Why do games need so much storage space?

Let’s have a look at why games need so much storage space. The biggest reason is texture data. 4K textures are becoming common, and a single uncompressed 4K texture with an alpha channel is 67MB. Granted, most textures are stored in a compressed format, but modern games have thousands of textures, so things add up fast. And most models are going to use more than a single texture.

Let’s take a simple rock for example. The model itself probably has less than 1K triangles, which even stored in a bad uncompressed format is only a few KB. But when the rock is close to the player and can take up a large percentage of the screen, it may require a 4K texture. And this is just the color texture, which describes how the rock looks, think of it as an image of a rock surface. But just that texture alone isn’t going to look great. In nature, most rock surfaces are very uneven, they have lots of tiny bumps, cracks, and imperfections. These features are not modeled in the 3D model. Instead, they are saved in a normal map, which is another 4K texture, that describes the imperfections on the surface so the lighting calculation can include them and make the rock look a lot more realistic.

And it doesn’t stop there. The rock can have a specular map, that describes how reflective the different parts of the rock are, a precomputed lightmap, that stores some static lighting information, or a secondary dirt texture, that is mixed with the rock texture to add more detail. And there are many other types of textures the rock could theoretically use.

As you can see, just a single rock can have multiple textures, and there are multiple different rocks in a game, as well as hundreds, even thousands of other objects that also require multiple large textures.

The PC version of a game is also generally bigger than the console version, at least for the current console generation (PS4 and Xbox One). Because the console hardware is known and every player has the exact same hardware, developers can optimize the console version, so it has exactly the right amount of detail to run at 1080p 60 FPS. But PC players will have vastly different machines and to make sure the game looks as good as possible on the high-end systems, the PC download includes more details, even though the average player may not be able to use them. Maybe there could be different PC versions, so a laptop player could choose a smaller download, but I haven’t heard from any game that actually does it this way.

Storage speed

Besides raw capacity, disk speed is becoming more and more important. A lot of games feature a completely open world, where the player can move through the entire map without any loading screens. The size of such a game is often above 100GB. However, even higher-end graphics cards only have 8GB of VRAM. VRAM is the fast memory on the GPU and it is shared between the vertex data, frame buffers, and textures. Now how does a 100GB game fit into only 8GB of VRAM? Obviously it doesn’t, which means that when the player moves, new data has to be streamed from the disk constantly. This is where the speed of the hard drive is important. When the drive is too slow and a lot of data is needed at once, some of the data may not be ready when it is needed, which causes objects to pop in very late, and in the worst case even game freezes.

I’ll also mention Nanite, which is a system in the Unreal Engine 5 tech demo that can crunch down cinema-quality models to game quality in run time. It’s able to handle a large number of triangles, which removes the need for normal maps or LOD models (LOD = Level Of Detail, the further away from the camera a model is, the less detailed it is). The tech demo is running on the PlayStation 5 with its fast SSD and it is safe to assume that Nanite wouldn’t work with an old and slow HDD.

Microsoft Flight Simulator

A recent example of a game that I really wanted to try, but couldn’t due to storage space limitations, is Microsoft Flight Simulator. It’s an extremely demanding game for the whole system, but my PC should be able to run it on lower settings. However, it requires 150 GB of disk space plus some additional cache for streamed content. I only have a small SSD for my OS at the moment so it doesn’t fit on there. Maybe I could run it from an HDD, but I’m not sure how well that would work. Therefore, the next upgrade to my PC is going to be a decently sized SSD, so I can check out how good my local area looks in Flight Simulator.

Another game that I wouldn’t mind trying is Call of Duty: Warzone, but it needs a staggering 175GB of disk space. Warzone is free-to-play and Flight Simulator costs $1 to try in the Xbox Game Pass. For these games, the limiting factor isn’t the price, but rather the amount of free disk space you have available.

Photo by Mitsuo Komoriya on Unsplash

While a big HDD was sufficient for every game just a few years ago, these days, an SSD is required for many games. High-resolution textures are becoming the standard and when systems like Unreal’s Nanite are taking over, games may be using cinema-quality models soon. High-quality models, but especially textures add up very quickly and are the main reason for the huge storage demands. Besides raw storage space, these large assets also require fast disk speeds, so they can be streamed and processed on the fly. In the past, we only looked at the CPU, GPU, and RAM to judge a gaming system, but now the SSD is just as important as the rest of the system, maybe even more so.