Why is CPU Cache So Important? and What is it?

You’re probably asking yourself what the heck is CPU cache? And if you’re not I’m not sure why you’re on here.

As processors became more advanced they became much much faster, and your typical short-term memory (RAM) couldn’t keep up with the speeds of these new CPUs.

This is where CPU cache was born.

CPU used to display a CPU and caching of a CPU

CPU cache is really fast short-term memory that can read and write data faster than normal memory components in a computer. The CPU has three different types of cache L1, L2, and L3. The CPU first starts by checking the L1 cache which is the fastest, then L2, and L3 once the previous is full. It then sends the information it needs to the main memory systems in the computer and gets rid of what is not needed anymore.

What is CPU Cache?

CPU cache is the fastest type of memory that your CPU can access and is often referred to as SRAM or static RAM. What it does is, predict and store certain information that your CPU might need.

When this process is completed it is called a “Cache hit” and helps your CPU performance increase.

However, if your CPU predicts and stores the wrong information, this is called a “Cache miss”. Then, your CPU will lose some performance.

More likely than not your CPU will have already predicted the next function that your computer needs, and will help speed up the process.

There is another type of short-term memory that processes temporary information known as RAM. RAM is dynamic as opposed to your CPU that is static, and therefore it is referred to as (DRAM).

DRAM is typically what you think of when someone thinks of fast short-term memory, but due to the progression of CPU development, even the fastest type of RAM that you can afford was bottlenecking your CPU.

This is where they came up with the idea to add cache inside your CPU. With the adaptation of CPU cache, computer performance and speed rose, but even with the implementation of CPU cache CPUs still had a lot of potential that weren’t being used.

That’s wherein in the 1980’s they decided to split L1 cache which is your main CPU cache so that if your CPU had a cache miss it would be able to have a second chance at getting a cache hit, and this improved the CPU performance tremendously.

As CPUs progressed, even more, manufacturers implemented extra levels to cache called L2 and L3 which are all the types of cache your CPU uses in today’s age.

What is The Difference Between L1, L2, and L3 CPU Cache?

L1, L2, and L3 are all different types of cache that work together to help the CPU transfer and process information as efficiently as possible.

The key takeaway from this is that L1 cache is the fastest and smallest type of cache, L3 cache is the slowest, but the biggest type of cache and L2 meets as the middle ground between the 3 types of cache memory in the CPU.

As talked about at the beginning of this article these components of cache are the fastest memory that a computer has.

What is L1 Cache?

L1 cache also known as primary cache is the main type of cache that your CPU uses and it is separated into two different categories. First, there is L1 Data Cache, which keeps data on your CPU that might be performed.

An example of this is when you go into chrome settings, and you have the option to clear your browser cache. That is an example of data cache because it is storing little bits of information about every website you visit so that the next time you visit that website it will load faster.

Next, you have L1 Instruction Cache, which contains information and gives instructions for your CPU to execute them.

Both types of L1 Caches work together to improve and help your CPU perform functions at an optimal level.

What is L2 Cache?

L2 cache is bigger than L1 cache, but at the same time, it is also slower than L1 cache. L1 cache is usually measured in KB because of how small it is, whereas L2 cache can be multiple MB in size for a modern-day CPU.

With that being said the speed of L2 cache can be up to 75% slower than L1 cache.

What is L3 Cache?

Lastly, you have L3 cache which is the slowest type of cache in your CPU, but also the largest in size.

L3 cache is accessed when the CPU can’t find the data it needs in the first two levels of cache, hence why it is the largest and the slowest type of cache.

It is also different in the fact that the first two types of cache (level 1) L1 Cache, and (level 2) L2 Cache, are stored in each individual core inside the CPU, whereas (level 3) L3 Cache is shared between every CPU core as a whole.

How Much CPU Cache Do You Need for Gaming?

The short answer is it depends, and it doesn’t matter that much at all in actuality. The reason for this is that cache works differently depending on the model and architecture of the CPU.

Image used to talk about what cache has to do with Gaming

A CPU with less cache can outperform a CPU with a high level of cache, but having more cache in a CPU is just a perk in buying a higher-end processor.

Technically more CPU cache is better, but really any modern processor that is sold now has enough cache to handle any tasks you throw at it, so you shouldn’t be too worried about the amount of cache that is in your CPU.

What is Cache Hit?

Cache hit means that the CPU cache has predicted the data that it is going to use before it processes it. This speeds up the functions of the CPU because it is able to predict and get the data ready before it is used.

What is Cache Miss?

Cache miss means that the CPU cache has predicted the wrong data. Therefore, it will have to load up while the CPU is completing the function slowing the CPU down.

Lucas Coulson

I first got into building my own computer when I was around 12 or 13. The first computer I had ever built didn't work. So I kept researching to figure what I did wrong. I really enjoyed researching, learning, and building computers, so I decided to turn it into an online business, and here I am.

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