UEFI is the preferred booting firmware for current PCs with massive hard drives.
UEFI has a CSM mode feature that provides legacy BIOS compatibility for earlier operating systems. However, there is a catch as to whether or not you should utilize it.
My relative recently had problems booting into Windows on his PC. I discovered that he was using a non-UEFI-capable operating system. We had to enable CSM, and his PC booted normally.
Don’t worry if things are getting too complicated right now.
I’ll explain everything in this essay, including the difference between CSM Boot Mode and UEFI Boot Mode and when you should use each.
CSM vs. UEFI: A Comparison
| Maximum Disk Capacity | 2.2 terabytes (TB) | 9.4 zettabytes (ZB) |
| OS Configuration | 32-bi | 64-bit |
| Secure Boot Support | No | Yes |
| Disk Partition Type | Master Boot Record (MBR) | GUID Partition Table (GPT) |
| TPM Compatibility | No | Yes |
| Multi-Boot Support | No | Yes |
Check out this comparison chart to learn about the significant differences between CSM and UEFI BIOS modes.
Explained: UEFI and Legacy BIOS Mode
Before we go into UEFI and CSM boot mode, let’s review the basics of BIOS.
The conventional BIOS (Basic Input/Output System) is the “firmware” of your computer. The first piece of code executes when the computer is turned on.
It runs the OS boot loader, which launches all of the operating system’s applications and processes. The BIOS is responsible for initializing all hardware components in your computer, such as microchips and peripherals.
UEFI (Unified Extensible Firmware Interface) is a new substitute for the outdated BIOS system.
Because of its severe restrictions, it began supplanting BIOS in about 2007.
Legacy BIOS, for example, operates on a system known as MBR (Master Boot Record), which can only accommodate partitions of up to 2TB. Most current PCs utilize UEFI boot mode instead of the old BIOS mode.
A new component named “CSM (Compatibility Support Module)” was introduced as part of this shift.
What Exactly is CSM?
CSM is an abbreviation for Compatibility Support Module. It is a program with the UEFI firmware that allows newer computers to be backward compatible.
CSM boot allows you to execute traditional BIOS booting on a contemporary UEFI-based machine. If you’re using an older operating system or wish to boot from an old storage device that doesn’t support UEFI BIOS mode, this can be helpful.
Remember that BIOS and UEFI are two different forms of computer firmware. CSM, on the other hand, is only a function available in the UEFI configuration menu.
If you have a new computer with a current version of the Windows operating system, CSM is most likely deactivated by default.
Let’s examine the critical distinctions between CSM and UEFI to determine which is best for you.
CSM vs. UEFI: Hardware and Operating System Compatibility
Because it is based on the old-school BIOS, CSM is compatible with older devices and applications. If your computer has ancient components, you will likely need to use legacy BIOS booting.
UEFI, on the other hand, is a recent standard intended to use current computer hardware. Your motherboard must support UEFI mode to utilize it.
Furthermore, the UEFI BIOS is often found on 64-bit systems. Hence, CSM BIOS mode is required to boot 32-bit computers. For example, Windows versions before Vista SP1 (Windows XP, Windows 2000, Windows 95, and so on) do not support UEFI mode.
UEFI mode also enables native multi-boot, which allows you to install multiple operating systems on a single hard disk. You may select which one to boot from the UEFI boot menu.
Which Has a Better User Interface: CSM or UEFI?
- When it comes to UI and general user experience, UEFI dominates
- CSM has a Character User Interface (CUI), which only accepts keyboard input
- It’s also not as user-friendly or feature-rich as a UEFI interface
- On the other hand, UEFI is a more polished and user-friendly Graphical User Interface (GUI). It provides mouse input, shortcut keys, scrollbars, icons, and other features
Disk Partition Format: CSM vs. UEFI
The CSM BIOS Mode uses the MBR (Master Boot Record) disk partition table format, whereas the UEFI BIOS Mode employs the GPT (GUID Partition Table).
The main distinction between both disk partition formats is that MBR only allows for four primary partitions on your hard disk and supports disks up to 2TB in size. GPT format, when combined with UEFI BIOS, enables 128 divisions and disks up to 9ZB.
It’s also worth noting that some operating systems, such as Windows, require you to boot MBR drives with legacy/CSM BIOS mode and GPT disks with UEFI BIOS boot mode.
This is not a problem for Linux systems using the GRUB bootloader, which allows you to boot MBR drives in UEFI mode and GPT disks in legacy mode.
CSM vs. UEFI: Power and Speed Management
Because of “Fast Boot” support, UEFI boot mode may be nearly twice as fast as Legacy CSM boot mode. It reduces the number of devices needed to start the boot process.
Furthermore, UEFI starts rapidly from power-saving modes like sleep, reboot, and hibernation. Its capabilities let it circumvent the power-on self-test (POST) phase, which slows down a CSM boot system.
Not to mention that these speed disparities only pertain to startup time and not overall OS performance.
Which Security System is Better: CSM or UEFI?
Because CSM is based on the original BIOS mode, it lacks some of the security features of the upgraded UEFI version.
On the other hand, UEFI includes all of today’s security features, including secure boot modes and disk encryption.
Depending on your needs, you may or may not wish to utilize secure boot. On the other hand, an extra security check at the firmware level might be advantageous against rootkits and ransomware.
UEFI BIOS can only have problems or defects when the operating system attempts to load an incorrect driver or uninstall the firmware configuration.
Which is the Better Option for you?
This question has no definitive answer. CSM and UEFI have a place depending on your situation and requirements. But here’s my opinion:
If you want to use CSM BIOS booting mode, do the following:
- I want to install earlier operating systems (32-bit)
- Use hard disks that do not support UEFI booting regularly
- Do you believe your PC’s firmware has flaws or glitches?
- If you have a recent computer with a 64-bit operating system, use UEFI BIOS mode
- More excellent protection versus ransomware and rootkits is required
- On your PC, you will not be using legacy hardware or software
- Because of its improved security and compatibility with newer computers, CSM boot mode is gradually replaced with UEFI BIOS mode
How do I Enable/Disable CSM in UEFI BIOS Mode?
The specific process for enabling CSM mode varies depending on the motherboard brand. You may discover the setting by visiting the BIOS settings when the computer is loading up.
Under the “Boot” tab, you should find an option labeled “Launch CSM” or “CSM Support” in most circumstances. Turn the CSM boot system on or off, then save and leave the UEFI booting interface.
Once activated, your PC will restart in the selected legacy mode. If you can’t find the setting, it’s possible that your motherboard doesn’t support CSM.
How can you Tell if your Computer is in CSM or UEFI Mode?
Here’s how to determine which of the two boot modes your computer uses.
- On your computer, tap the Windows Search icon (or click the Windows key on your keyboard). Now, type “System Information” and press the enter key
- Find the entry that reads BIOS Mode and look at the value next to it. Either UEFI or Legacy will be shown
- If it says UEFI, you’re in UEFI BIOS mode, and the “Boot with CSM” option in the UEFI features menu is deactivated
- If it reads Legacy, you’re either running an older BIOS boot procedure or have CSM mode activated
FAQs
Is it better to turn CSM on or off in the UEFI BIOS?
Only use CSM mode to boot an old 32-bit operating system on a 64-bit machine or boot from an old hard drive partitioned with MBR. Aside from that, it’s best to have CSM legacy boot disabled.
Does CSM Mode Have an Impact on Performance?
Enabling CSM mode does not affect your operating system’s overall performance. However, due to the POST procedure and the lack of a Fast boot, it may significantly increase startup time.
As a result, it makes little difference unless you care about a few more seconds spent during the boot process.
Is CSM or UEFI required for Windows 11?
Windows 11 will not function with CSM enabled. To install Windows 11, your machine must support secure boot, which means it will only work in UEFI BIOS mode.
You may still use Windows 11 with Secure Boot disabled, but Microsoft does not encourage it since it might result in stability difficulties and a lack of Windows updates.
Is CSM Secure Boot supported?
No. Secure Boot is a feature of the UEFI, or Unified Extensible Firmware Interface, mode. It does not, however, function with CSM enabled or in any old BIOS environment in general.
Because newer Windows operating systems, such as Windows 8, 10, and 11, need Secure Boot, they cannot be used with CSM or Legacy BIOS systems.
Conclusion
I hope you now understand everything there is to know about the CSM and UEFI systems and the distinction between the two boot modes.
To summarize, CSM is a UEFI mode that emulates previous BIOS systems and provides backward compatibility. It’s helpful if you wish to run older operating systems or storage devices that aren’t compatible with the UEFI system.
UEFI mode is the preferred option for most contemporary operating systems and machines. It is typically quicker, more practical, and more secure.
