What Is CSM Support in BIOS? Enable or Disable?

CSM, or Compatibility Support Module, is a part of the computer’s firmware called UEFI. It helps the computer work with older systems and devices that were designed for the traditional BIOS. In simple words, CSM allows your computer to work with older software and hardware that might not work with the newer UEFI system.

Why is CSM Useful?

Older Operating System Compatibility

CSM lets you use older operating systems that were made for traditional BIOS, so you can still use them on newer computers.

Older Hardware Support

CSM, or Compatibility Support Module, is a part of your computer’s firmware that helps it work with older hardware devices that might not be compatible with a newer system called UEFI. It’s like USB Legacy Support which ensures older USB devices can be used with modern computer systems. UEFI is like a bridge between your computer’s hardware and the operating system, like Windows. It helps your computer start-up and makes sure everything is working correctly before the operating system takes over. In simple words, CSM allows your computer to work with older devices that might not work with the newer UEFI system. This is helpful if you have an older printer, scanner, or other hardware that you still want to use with your computer

Virtualization Software Compatibility

CSM, or Compatibility Support Module, is a part of your computer’s firmware that helps it work with older systems and devices, including older operating systems. In the context of virtualization software, CSM can sometimes improve compatibility and performance when running older operating systems within the virtual environment.

Virtualization software allows your computer to run multiple operating systems at the same time, which can be useful for testing new software, running older programs, or using different operating systems for different tasks. When you enable CSM, it provides a more familiar environment for the older operating systems, making it easier for them to run smoothly within the virtualization software.

What is UEFI and How is it Different from BIOS?

UEFI (Unified Extensible Firmware Interface) and BIOS (Basic Input/Output System) are both types of firmware used in computers to initialize the hardware and load the operating system during the startup process. They serve the same purpose, but UEFI is a newer and more advanced system compared to BIOS. Here are some key differences between UEFI and BIOS:

1. Disk Support: UEFI supports drive sizes up to 9 zettabytes, while BIOS only supports up to 2.2 terabytes.
2. Boot Time: UEFI provides faster boot times compared to BIOS.
3. Operating Mode: UEFI runs in 32-bit or 64-bit mode, whereas BIOS runs in 16-bit mode. This allows UEFI to provide a graphical user interface (GUI) that can be navigated with a mouse, while BIOS only allows navigation using the keyboard.
4. Partition Support: UEFI uses the GUID Partition Table (GPT) for storing information about hard drive data, while BIOS uses the Master Boot Record (MBR).
5. Security: UEFI supports secure boot, which helps prevent the computer from being damaged by malware.

Although UEFI offers more advanced features and benefits, some older hardware and software may not be compatible with it, so BIOS is still available as a fallback option. The choice between UEFI and BIOS depends on your specific needs and hardware.

When to Enable or Disable CSM Support

You should enable CSM support if you need to use an older operating system or hardware that relies on the legacy BIOS interface. Enabling CSM allows your computer to boot in legacy mode, providing compatibility for these older systems. On the other hand, you should disable CSM support if you are using a modern operating system like Windows 10 or Windows 11, which supports UEFI and Secure Boot. Disabling CSM can help improve security and enable features like Secure Boot, which helps protect your system from unauthorized access and malware.

How to Enable or Disable CSM Support

To enable or disable CSM support, follow these general steps:

Turn on your computer and press the right key to access the BIOS or UEFI settings (usually F2, F10, or DEL).

Each motherboard brand has different menu to change CSM setting.

Asrock Motherboard:

1. Go to Boot > CSM (compatibility Support Moduled)
2. Choose Enable or Disable.

Asus Motherboard:

1. Go to Boot >Boot/ CSM (compatibility Support Moduled).
2. Choose Enable or Disable.

MSI Motherboard:

1. Go to the Settings > Advanced menu.
2. Find the Windows OS Configuration CSM > BIOS CSM/UEFI Mode.
3. Choose CSM to enable, and choose UEFI to disable it.

For other motherboard brand, menu location to enable or disable CSM Support should not too much different.

Drawbacks Of Using CSM In a Computer

There are several drawbacks to using CSM (Compatibility Support Module) in a computer:

1. Performance Impact: Enabling CSM may introduce a slight performance impact due to the added emulation layer for the traditional BIOS interface.
2. Limited Security Features: CSM does not support features such as secure boot or full disk encryption, making it less secure than UEFI.
3. Incompatibility with Modern Features: CSM does not support some modern features like faster boot times and support for larger drives that are available with UEFI.
4. Gradual Phasing Out: CSM is gradually being phased out as UEFI becomes the mainstream boot mode, which means that support for CSM may become limited in the future.

If you’re using a modern operating system and hardware that supports UEFI, you may not need to enable CSM. Disabling CSM can provide better security, compatibility with newer systems, and faster startup time

Hardware That Still Requires CSM Support.

Hardware and operating systems that may still require CSM support include:

Hardware:

1. Older expansion cards, such as PCI and PCI Express devices, rely on the BIOS interface for communication and do not have UEFI-compatible firmware.
2. Legacy peripherals that lack UEFI-compatible drivers or firmware.

Operating Systems:

1. Windows 7: While Windows 7 can support UEFI, it may require CSM for compatibility with certain hardware components or drivers.
2. Windows Vista: This older operating system may require CSM support for compatibility with UEFI systems.
3. Windows XP: As an even older operating system, Windows XP may need CSM support to function on modern UEFI systems.

Windows 8, Windows 10, and Windows 11 do not need CSM support, as they are designed to work with UEFI firmware. These modern operating systems include native UEFI support, which provides better security, faster boot times, and compatibility with newer hardware features compared to CSM. If you’re using one of these operating systems, you may not need to enable CSM, and disabling it can provide better performance and security

Why Is My Computer Screen Black After Turning On CSM?

A black screen after turning on CSM could be due to various reasons, such as incompatibility between your hardware and the CSM settings, or issues with your graphics card or display output. Tried using an alternate monitor or TV and if the issue persists, it’s likely not a problem with the display itself. Here are some steps you can try to resolve the issue:

1. Reset your BIOS settings: Turn off your computer and unplug it from the power source. Open the computer case and locate the CMOS battery on the motherboard. Remove the battery for a few minutes, then reinsert it and power on your computer. This will reset your BIOS settings to their default values, which may resolve the issue.
2. Check your graphics card: Ensure that your graphics card is properly seated in its slot and that all necessary power connectors are securely attached. If you have an integrated graphics card, try connecting your display to the motherboard’s display output instead of the dedicated graphics card.
3. Update your BIOS: Check your motherboard manufacturer’s website for the latest BIOS updates and follow their instructions to update your BIOS. This may resolve compatibility issues between your hardware and the CSM settings.
4. Disable Secure Boot: If you have enabled Secure Boot along with CSM, try disabling Secure Boot in your BIOS settings and see if the issue persists.

CSM support in BIOS helps your computer work with older software and devices. However, if you have a modern computer with a newer operating system and hardware, it’s usually better to use UEFI instead of CSM. Always think about your specific needs and hardware when deciding whether to enable or disable CSM support.