Yes, a motherboard can turn on without a CPU, but this process requires the BIOS flashback feature. BIOS flashback is a feature on a few motherboards that permits users to effortlessly update the BIOS version without entering BIOS mode or turning on the computer. If your motherboard has this feature, you can turn it on without installing a processor, graphics card, or memory; otherwise, it won’t start.

Although you can turn on a motherboard without connecting a processor, it’s only beneficial if you want to update the BIOS. There isn’t much use for this function since you can’t perform any task on the computer. Another fact to remember is that turning on the mother circuit without the following components attached has no harmful effects; only the motherboard will not access the CMOS instructions.

Turning on motherboard without CPU

There are two situations when you can think of turning on a motherboard without putting a processor on. Those are as follows:

  1. You wanted to update the motherboard’s BIOS without a processor, maybe since you don’t have a processor or it has stopped working.
  2. You wanted to test your motherboard without putting a CPU on since something unusual is happening in your system.

Turning on a motherboard without a CPU can help in both these conditions. Therefore, we’ll learn to test and update BIOS in this article’s section. Let’s start

Updating BIOS without a CPU

Here is a step-by-step guide to updating the BIOS without connecting a CPU to a motherboard:

Step 1: Download BIOS from the Official Manufacturer’s Website

  • Go to the official website of the motherboard manufacturer (ASRock, Asus, Gigabyte, or MSI).
  • Search for your motherboard model and search for the latest BIOS updates. 
  • Download the latest BIOS update from the “Support” or “Downloads” section.

Step 2: Extract and Rename the BIOS File

  • Extract the downloaded file (likely a ZIP folder).
  • Rename the file name for ASRock, Gigabyte, or MSI motherboards as follows:

ASRock: creative.rom

Gigabyte: gigabyte.bin

MSI: msi.rom

Step 3: Format the USB Drive As FAT32 and Add BIOS File

  • Plug in the USB flash drive into the system.
  • Format the drive as FAT32.
  • Transfer the renamed BIOS file to the root of the USB drive.
  • Safely eject the USB drive.

Step 4: Connect Your Power Supply Unit (PSU)

  • Connect the power supply unit to the motherboard, 24-pin main power connector, and 8-pin CPU power connector to their accurate spots.
  • Connect the power supply unit to a wall outlet and turn it on

Step 5: Enter the BIOS Setup and Start the Flash Process

  • Connect the USB drive to the motherboard via the USB BIOS Flashback port.
  • Press the Flashback button next to the port; keep pressing it for at least 3 seconds until the light blinks.
  • The latest BIOS would have been installed into the motherboard up to this point. 

Testing a motherboard without a CPU

You must ensure your motherboard is set up on a secure surface and linked to the power supply unit. You won’t be able to test the motherboard by turning on your computer or anything similar, but you will be able to test it through a series of beeping noises or LED flashes from the motherboard. All that is left for you to do is to search and locate the Power Switch pins.

Step 1: Make your Motherboard Ready.

  • Remove your motherboard from its packaging and set it on a conductive surface, such as anti-static foam or cardboard, or on the box itself.
  • Your motherboard will be destroyed if the solder points at the bottom make contact with any metallic surface when you switch it on.

Step 2: Connect the Power Connectors.

  • Connect the power connectors from the power supply unit to the motherboard in appropriate slots.
  • Most motherboards include a 24-pin and an 8-in power connector for the motherboard and the CPU, respectively.
  • If your motherboard and system are older, a 4-pin connection is also included with the power supply unit.

Note: The 4 Pin power connector only provides roughly 140 watts to the CPU, compared to the 8-pin power connector, about 280 watts. Learn more about wattage if you have confusion.

Step 3: Install the Additional Components (optional).

  • You can now install any additional parts, including RAM, hard drives, and graphic cards.
  • But these parts will be useless and of little value without a CPU.

Step 4: Attach the Power supply Unit to the Wall Outlet.

  • The next step is to power up the power supply unit by plugging it into the wall socket.
  • You can even place the PSU on a non-conductive surface to prevent any issues.
  • It’s suggested to use rubber shoes and non-conductor hand gloves when testing a motherboard or to do anything related to power.

Step 5: Turn on the Motherboard.

  • The next step is to turn on the motherboard; you can use the switch pins or jump-start method.
  • For the switch-pins method, locate the Power Switch Pins on the motherboard and connect the power switch cable. Once connected, simply turn on the motherboard by pressing the power button.
  • If you want to use the jump-start method, you have to touch both power switch pins on the motherboard; you can use a flat-head screwdriver or some other metallic wires. 

Step 6: Check whether your motherboard is working.

  • Up to this point, your motherboard should give you some signs of life if it’s in good working condition.
  • Those working signs can be beeping sounds, blinking LEDs, or other signs to show that a motherboard is turned on.
  • If you don’t get any sign of life in your motherboard or it’s not working as expected, it’s more likely dead.

Note: You must purchase a new motherboard and put that into your computer to take it back to life. Suppose you don’t have much knowledge about choosing a motherboard. In such a case, you can read this motherboard buying guide to make things easier. 


A motherboard can start without a CPU but can only do a small number of tasks. It’s helpful when you want to update the BIOS using the BIOS Flashback function or want to test the motherboard without connecting components like CPU, graphics card, and memory. But you must know all the steps for testing or updating BIOS, which we have also covered in this article. You must read and carefully follow all the steps whether you’re testing or updating the BIOS version.

Frequently Asked Questions

Why doesn't a motherboard light up?

Your computer may not start up if your power supply is malfunctioning. Replace your power supply first before doing anything else. Your computer won’t start up if your motherboard is damaged because it lacks the connections and circuitry necessary to support the hardware that is mounted on it. Most likely, you have already ruled out these two possibilities as possible reasons for your issue.

Why is a motherboard so important in a PC?

The sort of storage device, memory module, and graphics card that may attach to your computer is also determined by the hard drive (among other expansion cards). A good motherboard will unquestionably enhance your PC’s performance and, consequently, your workstation experience.

A top-tier ATX motherboard is unquestionably the way to go if we’re talking about practical performance increases like quicker storage device transfer rates, more LAN bandwidth, faster rendering times, and general system reliability.

Abdullah Sarfraz
Myself Abdullah Sarfraz and I am an SEO. My hobby is reviewing the latest tech-related products. For the past few years, I am working on amazon affiliated sites therefore, I came to know my interest and chose this field, now I have good experience in it.