What Is CSM In BIOS? [Explained!]

CSM, or Compatibility Support Module, helps older computer systems that rely on legacy BIOS to work on new computers. It acts like a bridge, making sure both old and new systems can run smoothly together.

When we talk about CSM in the BIOS, it’s apparent that CSM is closely connected to the BIOS. However, before we know what CSM is, let’s discuss BIOS.

BIOS stands for Basic Input/Output System, which essentially manages input and output operations. It’s a type of firmware stored on the ROM chip on the motherboard, facilitating communication between the computer’s hardware and operating system.

Acting as an intermediary between the CPU and data flow, BIOS plays a crucial role in initializing the computer’s hardware during the startup process.

When you turn on your computer, BIOS configures the hardware, contributing to the hardware initialization during booting. It’s the first component to run when your computer starts up.

Notably, BIOS has a text-based interface, and its primary focus is on the booting process. It conducts tests on the hardware to ensure proper functionality and compatibility throughout the booting process.

Moreover, BIOS stores configuration information in complementary metal-oxide-semiconductor (CMOS), allowing users to access and modify these settings.

Originating with the IBM original PC, BIOS has a long history and is commonly used, especially in older computers. In modern systems, BIOS is now stored on flash memory, showcasing its evolution over time.

What Is The Purpose of CSM in BIOS?

Now that you have a good understanding of BIOS, let’s explore the Compatibility Support Module (CSM).

CSM, short for Compatibility Support Module, is all about ensuring compatibility, especially for operating systems and other systems. But compatibility for whom? Well, CSM provides backward compatibility for systems designed to work with the legacy BIOS.

Think of it this way: CSM is like a helpful link between advanced firmware and the older BIOS. The advanced firmware we’re talking about is UEFI. CSM steps in to make sure that when newer systems operating on UEFI are introduced, older systems can still function on the updated hardware.

This is beneficial because, while UEFI brings advanced features, having CSM ensures that older systems can still operate. It adds a touch of diversity to the compatibility landscape.

With CSM, even systems using the old MBR scheme for booting can continue to work. So, basically, CSM acts as a bridge, filling the gap between older legacy systems and their modern counterparts.

What Is UEFI, And What Sets UEFI Apart from BIOS?

UEFI wooden letters written on blue background.

UEFI stands for Unified Extensible Firmware Interface, representing a modern and advanced form of firmware designed to replace the traditional BIOS firmware.

As technology progressed, it became evident that updates were necessary to accommodate new operating systems and modern hardware. The introduction of UEFI ensures a more sophisticated system to keep up with these advancements.

To provide a clearer understanding of the advantages that UEFI brings with its advanced features and how it distinguishes itself from the traditional BIOS, I’ve compiled a table below:

EfficientThe UEFI firmware makes your computer start up faster. It uses hardware optimization to quickly get the system going. The initialization process is straightforward but speedy, making it an ideal choice for users.
Graphical User InterfaceThe UEFI firmware has a graphical user interface, which makes it more attractive and appealing to users. This GUI comes with mouse support, making it easy to interact with and configure the settings.
Enhanced SecurityOne great feature is the secure boot, offering extra security to users. It ensures that only genuine systems and firmware run during the booting process, effectively preventing unauthorized access.
Better AccommodationUEFI supports the GUID Partition Table (GPT), allowing for the use of larger storage devices. These devices can be bigger than 2.2 terabytes, which is quite advantageous.
Modular ArchitectureSince UEFI has a modular structure, the firmware and devices operate independently without relying on each other. This guarantees flexibility, allowing for individual updates without the necessity of a full system update.
Connectivity FeaturesBecause UEFI supports networking protocols, it enables various activities on the network such as network updates. This is particularly useful, especially in environments where managing things over the network is common.
Some of the main advantages of UEFI

Should You Enable Or Disable CSM BIOS?

A confused girl.

When faced with this question, what I usually suggest is that it depends on personal preference. There are certain factors to consider when deciding whether to disable or enable your account.

For BIOS, if you’re using older hardware or software like Windows 7 or older Linux versions, these are compatible with BIOS but not with UEFI. In this case, enabling CSM is a preferable choice.

However, for brand-new hardware with software like Windows 8 or 10, there’s no need to enable BIOS because it’s only compatible with UEFI.

So, it’s essential to analyze your situation before deciding on an option.

The decision becomes particularly challenging in systems with UEFI-only or BIOS-only modes because once you choose a mode, you cannot reverse it. Therefore, making a sensible choice and selecting the right approach is crucial.

What Are The Steps To Enable CSM BIOS?

A guy toggling the option on.

If you want to enable the CSM option, keep in mind that the enabling process might vary slightly based on your PC’s BIOS version like ASUS, Gigabyte, ASRock, or MSI.

However, for a general idea, follow these steps:

  1. Start your computer.
  2. Press and hold the F2 or Delete key. This will take you to the BIOS settings. (The key may vary between different PCs, but if it doesn’t work, your Windows will guide you on which key to press).
  3. Find the “BIOS” or “BIOS options” section. Click on it.
  4. Click on the “Compatibility Support Module” or “Legacy Boot” option.
  5. Set it to “enabled”.
  6. After that, you’ll have to click on “Boot Order” or “Boot Priority.”
  7. Make sure the storage device is set as the first boot option.
  8. Click on “Save and Exit” or press F10 (or another key depending on your computer).
  9. Your computer will restart. The system will have CSM enabled, making it compatible with the BIOS legacy system.
How to enable CSM in ASUS Motherboard

How To Disable CSM BIOS?

Toggled off.

If you’ve decided to disable CSM, the process is similar to enabling it, but of course, it may vary based on your BIOS version.

Here are the steps to disable it:

  1. Start your computer.
  2. Press and hold the F2 or Delete key to access the BIOS settings (the key may vary between PCs).
  3. Find the “BIOS” or “BIOS options” section. Click on it.
  4. Now you can opt for the “Compatibility Support Module” or “Legacy Boot” option.
  5. Set it to “disabled.
  6. After that, you’ll have to click on “Boot Order” or “Boot Priority.”
  7. Ensure the storage device is the first boot option.
  8. Click “Save and Exit” or press F10 (or another key depending on your computer).
  9. Your computer will restart with CSM disabled, making it compatible with the UEFI system.

Is It Possible To Switch Between CSM And UEFI BIOS Modes?

Yes written in comic style

Yes, it’s entirely possible to switch between UEFI and CSM BIOS systems, depending on your computer.

However, remember that when you switch from one mode to another, you’ll need to install that mode before using your computer. It’s a good idea to have a backup of both modes.

The process to switch is the same as enabling or disabling the CSM.

To Conclude

  • Bios is a crucial part of your computer that helps it start and communicate with its hardware and software.
  • CSM in BIOS ensures older systems can work on newer computers, creating a link between legacy and modern technologies.
  • UEFI is an advanced system replacing BIOS, offering features like faster booting and a graphical interface.
  • Deciding whether to enable or disable CSM in BIOS depends on your system. Newer systems might benefit from UEFI, while older ones work better with CSM.
  • To enable CSM, start your computer, access the BIOS settings, find the Compatibility Support Module or Legacy Boot option, and set it to enabled.
  • To disable CSM, start your computer, access the BIOS settings, find the Compatibility Support Module or Legacy Boot option, and set it to disabled.
  • Yes, it’s possible to switch between CSM and UEFI BIOS modes, but the process depends on your computer.

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