How To Identify BIOS Chip On Motherboard?

BIOS stands for Basic Input/Output System. This is a simple computer program that is used when a computer turns on. You could think of it is as the first operating system that talks directly to the hardware.

Here I will talk about how to identify BIOS chip on motherboard. You could use this information perhaps for your knowledge or in case if you want to perform manual repair.

Essentially, BIOS is stored permanently in a chip. This is a fairly small chip located often near the CMOS battery socket.

However, the exact location can vary from motherboard to motherboard.

So How To Identify BIOS Chip On Motherboard?

You can identify the BIOS chip on a motherboard in two ways.

  1. Using the Motherboard Manual
  2. Through Physical Inspection

I explain each below.

1. Using Motherboard Manual to Identify BIOS Chip

All motherboards manuals have the motherboard layout diagram that highlight all the critical components located on it.

This includes sockets, slots and chips.

As such, using your motherboard’s manual, you can easily pin point the location where you would find the BIOS chip.

how to identify BIOS chip on motherboard
BIOS Chip Location on Gigabyte GA-P67A-UD3.

With the help of the manual, I can easily tell that the BIOS chip on my motherboard is located under the RAM slots and close to the motherboard’s chipset.

Here is the actual location of the BIOS chips on the motherboard:

Motherboard bios Chip Location
Location of the BIOS chip on a Gigabyte GA-P67A-UD3

Looking at the motherboard’s manual can save you from the hassle of going over each chip one by one on a motherboard in the effort to identify the BIOS chip.

2. Identifying BIOS Chip Through Physical Inspection

You can rely on the good old physical inspection as well to identify the BIOS chip.

This motherboard has 2 BIOS chips. M_BIOS is the main BIOS; the B_BIOS is the backup BIOS if going back to factory default is ever needed.

Almost all of the critical components on a motherboard have labels indicating exactly what they are. 

BIOS chips often have the labels M_BIOS, UEFI, BIOS etc

The motherboard above, for instance, has two BIOS chips which are clearly labelled as M_BIOS and B_BIOS respectively.

Also Read: What Happens When CMOS Battery Dies?

Why Some Motherboards Have Two BIOS Chips?

Some motherboards have two BIOS chips whereby the primary M_BIOS acts as the Main BIOS chip where as the secondary or the B_BIOS chip acts as the Backup.

The Main BIOS chip contains your preferences and settings. The BIOS in this chip can be manipulation by the user.

The Backup BIOS chip contains the factory default settings. If anything were to go wrong with the Main BIOS chip i.e if it fails or you have messed up with the settings, the Backup BIOS chip then takes over. 

Do Not Mistaken CMOS Battery With BIOS Chip

CMOS Battery

Rookies often make the mistake of thinking that the CMOS battery is somehow where the BIOS is also located.

That is not the case.

The CMOS battery serves the purpose of powering up the CMOS chip where the BIOS stores the date, time and system configuration.

CMOS battery is often used for resetting the BIOS settings to default. To reset the BIOS, you can simply take the battery out. Wait for 15 seconds and then plug it back in.

Also Read: How to Reset Motherboard?

Removing and Replacing the BIOS Chip

You should try not to tamper a lot with the settings of the BIOS. More often than not, you can literally break your motherboard if BIOS settings are ruined.

In the unfortunate case, if your BIOS chip has malfunctioned and you want to manually replace it, then identifying it is the first step.

Once you have identified the location of the BIOS chip, you will need to identify its manufacturer, type and the package design.

There various package type (shape) of the chips. This include

  • PLCC: Plastic Leaded / Leadless Chip Carrier
  • DIL: Dual in Line Package
  • SOP: Small Outline Package

The different package designs have different pin counts as well.

How To Identify BIOS Chip On Motherboard
BIOS Chip. Source:

For instance, the chip above has the following details:

  • Manufacturer SST
  • Part Number: 49LF004B 33-4C-NHE
  • Package Type: PLCC-32 (7 pins top and bottom, 9 pins left and right = 32 pins)

Often the inscription on the BIOS chips are very tiny. As such, you may need a magnifying glass in order to find the exact details of the chip.

Once you have identified exactly what motherboard chip you have, you can look it up online on stores like or

bios chip on ebay
SST 49LF004B 33-4C-NHE BIOS chip on ebay

Of course the actual process of manual replacement requires handyman skills. 

A slight mistake when removing or replacing the BIOS chip can further damage your motherboard.

Also Read: Do Laptops Have PCIe Slots?

Final Words

Identifying BIOS chip on motherboard is simple. The exact location can easily be found using the motherboard’s manual or through physical inspection.

In order to replace the BIOS chip, however, you need to identify its make and model. For this, you will need to read the inscription written on top of the BIOS chips.

Photo of author


Atif Qazi
Atif Qazi is the founder of PCGuide101. He is a digital nomad who loves everything PC. He is a PC builder, tech enthusiast, engineer, and a lover of single player lore-rich RPG games.

2 thoughts on “How To Identify BIOS Chip On Motherboard?”

  1. Thanks for the write up, do you have an email or telegram where you can always help out with some issue pertaining laptops.

    Thanks alot


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