Can CPU Instructions Be Stored In RAM?

The CPU’s purpose in a system is to execute the instructions from a computer program. However, with all the processes it needs to execute, it will eventually run out of storage for those instructions, right? So, can these CPU instructions be temporarily stored in RAM?

CPU instructions can be stored in RAM and the CPU cache, HDD, and SSD. RAM is volatile memory, so it’s suitable for storing data temporarily. Typically, CPU instructions are moved from your slower storage (SSD and HDD) to RAM, and eventually, the CPU cache is processed.

How CPUs Store and Execute Instructions

Close up of RAM modules installed onto a motherboard.

When you run a program on your computer, it will send instructions to the CPU for execution. This includes all the operations and operands the computer needs to ensure everything runs smoothly.

Let’s talk about the stages of operation that a CPU goes through when you’re using a computer program.

1. Fetch the Instructions From the Storage

The CPU, no matter how powerful it gets, will always rely on instructions in the memory to operate. When you perform a specific task, the CPU will fetch all the instructions for executing it from your system’s memory.

When you perform a task, and there’s no available instruction in the memory for the CPU to execute, one of these things will happen:

  • The system will force the program to halt its operation. Many people refer to it as a program crash or freeze. The solution for this may vary depending on the type of missing instructions or tasks needed to load the instructions.
  • The operating system will reallocate resources to the program. This will provide the system with enough resources to prevent the program from crashing. However, it may take a while before the CPU instructions load, resulting in a program freeze.
  • The program won’t run on your computer unless you add more memory. This usually happens to older systems with limited resources trying to run resource-intensive apps. When this happens, you can only fix it with a system upgrade.

One of these three happens when you start a program for the first time, so it takes a while for the system to load the application.

However, if you have enough storage in your memory, the next time your CPU needs to fetch these instructions, it will be faster because the CPU can easily fetch them from memory.

2. Decode the Instructions From the Storage

The instructions coming from your system’s memory aren’t always straightforward. So, the CPU needs to decode all the instructions it gets before executing the task. It also needs to determine the operation the instructions represent and the operands it needs to use.

This process needs to happen because it allows the CPU to determine the operations it needs and the most efficient way to perform them. Without these instructions, your program will stop working, and the system will terminate its operation, resulting in a crash or forced shutdown.

3. Execute the Decoded CPU Instructions

Once the CPU decodes the instructions, it can execute the operation smoothly. This is when you can interact with the program you’re using, making it possible to work on the tasks you’re trying to perform.

However, throughout the program’s operation, your CPU must continuously fetch and decode instructions to ensure you can perform the tasks you need from your computer.

If the CPU fails in one of these steps, it may result in a program or system crash because the CPU wouldn’t have the proper instructions to execute the instructions.

4. Store the Result After Executing the Instructions

The CPU will store instructions in RAM whenever you complete a task. This makes it easier for the CPU to access in the future, especially while it’s in operation.

These instructions will continue to pile up as you perform more tasks. If you don’t have enough storage in your memory, your system will run out of space for these instructions, resulting in a program or system crash.

The more RAM you have installed in your computer, the more instructions can be stored, allowing your computer to work faster on the tasks you need. However, since RAM only serves as temporary storage, all its stored instructions will be discarded as soon as you restart the system.

This is why people with older systems have to restart their computers more frequently than those with more RAM. The lack of storage for these instructions can make it difficult for the computer to fetch, decode, execute, and store seamlessly without crashing.

CPU Cache vs. RAM: Which Is Better for CPU Instructions

There are four types of memory storage that you can use to store CPU instructions. However, modern computers typically only use two storage spaces for CPU instructions: CPU cache and RAM.

CPU Cache

The CPU cache is a type of memory that provides quick access to the most frequently used instructions. They can either be within the CPU, which makes it easier to fetch instructions, or in the motherboard, which is still close to the CPU for quick access.

Here are the three types of CPU cache in a computer:

  • L1 Cache is the smallest and fastest storage that the CPU can access.
  • L2 Cache has bigger storage than L1, but it’s also slower.
  • L3 Cache is the largest and the intermediary between CPU instructions on the RAM and the CPU.

RAM (Random Access Memory)

RAM is the fastest storage that you can use for CPU instructions (aside from CPU cache). It typically ranges from 1GB to as high as your motherboard supports. You’ll even find some motherboards supporting up to 1024 GB (1 TB) of RAM!

Instead of the linear access you get from an HDD or SSD, the RAM can provide “random access” to the CPU, making it easier to fetch, decode, execute, and store the instructions.

However, since the RAM is a separate component installed on the motherboard, the CPU will take much longer to fetch and store the instructions. That’s why it’s reserved for applications you’re using rather than the core operations your system needs.

The more programs you use on your computer, the more instructions are stored in the RAM. When you run out of memory space in your RAM, your system will intervene whenever the CPU needs to store new instructions.

This is why computers with less RAM space typically run slower than those with plenty of memory storage for CPU instructions.

CPU Cache vs. RAM: Which Is Better for Storing CPU Instructions?

Both have their pros and cons. However, if we compare the two based on pure speed and raw performance, CPU cache, even L3 cache, will always be faster because of its proximity to the CPU and its architecture.

However, since they’re costly to manufacture, you can’t use them to store a whole lot of CPU instructions for the applications that you’re using. So, RAM is still a better choice, thanks to its larger capacity.

It provides an excellent speed-to-capacity ratio and works well with almost every application. Aside from this, you’ll also have the option to upgrade your RAM if you need more space, which isn’t possible with a CPU cache.

Other Types of Storage for CPU Instructions

Aside from the CPU cache and RAM, your computer uses two other types of storage for storing CPU instructions. Both provide a smoother user experience when using your computer. However, either method requires you to configure your system before being used as storage for CPU instructions.

SSD Cache

Some solid-state drive (SSD) manufacturers provide “SSD caching” capabilities to assist a system with lower RAM space. This can give your system an alternative memory space that works faster than an HDD when storing CPU instructions.

If you set up your computer to utilize SSD caching, you’ll have a place to store frequently used instructions, which are useful when using resource-intensive tasks. The downside is that you’ll have to sacrifice some storage space for data.

SSD caching can be achieved by installing the SSD directly into a storage controller or, more commonly, with the help of an SSD caching program.

Note that everything from the speed of your SSD to the program you choose affects how effective the SSD cache is.

Virtual Memory

If you always run out of memory space for the processes your computer is working on, you can assign a part of your HDD to serve as virtual memory. This is the slowest option but is the most affordable way to increase the memory in your system.

HDD is slower than SSD or RAM, but it allows you to have more storage for CPU instructions without upgrading your system’s memory or physically adding more RAM sticks.

It also enables the operating system to manage memory more efficiently without requiring the user to interfere with the computer’s operation.

The operating system moves the instructions you’re not using to the virtual memory. By doing this, the operating system can easily create more space in the RAM for your current tasks while keeping the instructions for inactive programs readily available.

The only problem with using virtual memory is that it can significantly reduce the lifespan of the HDD. This is due to the frequent swapping of pages between the memory and the hard disk. 

Still, it allows you to get more out of an older system without needing additional physical memory for resource-intensive tasks.

One caveat with using an old HDD for virtual memory is that your system might freeze or crash if there’s a bad sector.

How To Avoid Running Out of Space for CPU Instructions

With all the processes a computer must go through when executing instructions, it’s normal to run out of memory space. Fortunately, there are a few things that you can do to prevent it from happening.

Here are some tips to help you get more out of your system without having to upgrade your RAM:

  • Close the programs that you’re not using. Even if you’re not using a program, its instructions will still be stored in the memory until you close it or restart your computer. If you only minimize the programs you’re not using, you’ll eventually run out of memory space for the CPU instructions required for the programs that you’re actively using.
  • Disable startup and background programs. Startup and background programs also require CPU instructions that force the CPU to go through the same fetch and store cycle even without using it. So, it would be best to disable your startup programs and those running in the background to ensure they won’t take up crucial memory space for your active programs.

If you still run out of memory for your CPU instructions despite configuring your system to create more storage, adding more RAM to your computer is the best way to handle it. It’ll be an easy and cost-effective upgrade if you have a couple of empty RAM slots on your motherboard.

This will provide enough space for more CPU instructions and help your computer work faster and smoother for other required tasks.

Tip: Unless you have extensive knowledge about RAM specifically and how it will perform with your motherboard, you might need to replace the existing RAM with the proper kit to upgrade RAM.