Why I care about CPU cache as a PC gamer: The obscure spec, explained

It’s easy to look strictly at the type of CPU and GPU you have when evaluating the kind of performance you’re likely to get in PC games. But beyond that lies another important stat, the CPU cache. Here’s why it’s so important in gaming and why it pays to maximize it.

What is the CPU cache?

The CPU cache is a high-speed memory unit located around the CPU that is used to store frequently accessed data and instructions from the main memory. The proximity of the cache so close to the CPU means that data can be retrieved a lot quicker than from the RAM memory itself, so having more cache can greatly speed up and improve the CPU’s performance.

What’s the cache’s role in PC gaming?

The above process applies to when you’re gaming too. Your PC’s CPU cache stores frequently used game data and instructions from the game you’re playing. By doing so, it allows the CPU to retrieve and process this information more quickly than if the CPU has to continually access your PC’s RAM.

The CPU cache is important for reducing latency, maintaining consistent frame rates, and preventing stuttering in games. This is especially the case when playing triple-A games that have high computational demands for things like complex physics. Without enough cache, your GPU is forced to wait on your CPU to process instructions, which can create a bottleneck that will slow down your game.

The type of game information stored in CPU cache can vary and include anything from AI algorithms to textures, models, or the instructions for rendering graphics. The more data a game has to process, the more useful it is to have a higher amount of cache that will keep your game running smoothly.

Further reading: The truth about PC gaming on SSDs vs. HDDs, tested with real data

How much CPU cache do you need?

How much CPU cache you need for optimal performance depends on the type of game you’re playing and other factors like the number of cores in your CPU. As mentioned, you’re going to want more cache to run triple-A titles with a lot of data.

In fact, having more cache is even more important than having more CPU cores when your CPU has a lot to process; this has been shown to be the case in testing.

In one test the testers demonstrated how a 67 percent increase in L3 cache netted a corresponding 18 percent increase in a CPU’s performance, while a 67 percent increase in the same CPU’s core count only netted a 6 percent increase in performance.

As a guide, the following cache sizes are suitable for most modern PC games:

• L1 cache: 64KB per core
• L2 cache 256KB per core
• L3 cache: 32MB to 96MB

As you can see there are different levels of CPU cache denoted by the letter L and their corresponding number.
L3 cache is generally the most important kind of cache for PC gaming, since it can store a larger pool of data that is often shared among the CPU cores, so you’ll want to pay most attention to how much L3 cache a CPU has.

How do you get more CPU cache?

As for obtaining more CPU cache, you can’t just go out and buy new cache and install it like you can RAM. Instead, the best way to get more cache is to upgrade your CPU, or if you’re building a new rig, to choose a CPU that has the most higher-level cache as possible.

The amount of cache a CPU has can be the standout difference between two CPUs with very similar specs. For example, the AMD Ryzen 9 7900X and the AMD Ryzen 9 7900X3D are both high-end processors from AMD’s 7000 series with the same maximum boost clock speeds of 5.6GHz, but the Ryzen 9 7900X3D has 128MB L3 cache compared to the Ryzen 9 7900X’s 64MB L3 cache.

The Ryzen 9 7900X3D’s additional cache and the fact that it sports AMD’s 3D V-cache technology means it performs better than the AMD Ryzen 9 7900X in cache-sensitive games.

For that reason, you’re going to want to compare the cache from different CPUs before you buy, as well as read a few benchmarks to get an overview of performance.

Further reading: Why I never buy the best gaming hardware for my PC