Many of you have asked us if it’s possible to test a motherboard without a CPU, and the answer is yes!
Testing your motherboard before installing a CPU can help you understand if the motherboard is dead. To test your motherboard, all you have to do is to connect the PSU to your motherboard, turn it on and see if the motherboard gives any signs of life, such as beeps or lights.
With that being said, keep in mind that the testing process will be completely different from other testing methods since you won’t be able to boot up the system or POST, and you will have to work with beeping codes and LED lights.
Why test the motherboard without a CPU in the first place?
It is normal to wonder if it’s necessary to go through the hassle of testing your motherboard without any components.
However, this extra step in the building process can save you a lot of time and headaches down the road. By testing your motherboard before installing a CPU, memory, and other components, you can be sure that it isn’t dead, making it easier to troubleshoot if you encounter any problems later on.
This is actually a standard process PC builders use when building a new system called the “pre-built bench test.” They do this bench test because motherboards are very sensitive and can easily get damaged during shipping.
If you do the pre-built bench test and the motherboard passes it doesn’t mean that your motherboard is good to go. It might have other issues that only show up when you have everything installed. But at least you will know it hasn’t arrived DOA (dead on arrival).
Now that we got that out of the way let’s get into how to test a motherboard without a CPU installed.
How to test a motherboard without a CPU?
To test your motherboard without a CPU installed, you’ll need only two things:
- A Power Supply Unit
- The Motherboard
1. Unbox the motherboard and make sure not to cause static damage.
The last thing you want to do is to cause static damage to the motherboard by not being careful. When taking it out of the box, hold it by the edges and try not to touch any of the component areas. Place it on a flat, non-conductive surface like the antistatic bag it came in or even the case box.
Make sure not to place it on anything metallic like a metal table, as this can cause static damage. Motherboards are pretty sensitive, and it only takes a tiny spark of static electricity to destroy your motherboard, so be extra careful.
2. Find the 24-pin power connector and the 4/8-pin CPU power connector on the motherboard.
The 24-pin power connector is usually located next to the RAM sockets, and the 4/8-pin CPU power connector is right above the CPU. If you’re unsure which one is, consult your motherboard manual.
3. Plug in the 24-pin power connector and the 4/8-pin CPU power connector to the motherboard.
Now that you found the power connectors on the motherboard, it’s time to plug the PSU cables into them. Finding these cables is pretty easy as they have labels telling you which connector they go to.
4. Connect the power supply unit to a power outlet and turn it on.
Now that everything is plugged in, it’s time to connect the power supply unit to a power outlet and turn it on. At this point, there will probably be no signs of life since you haven’t turned on your motherboard yet, which is fine.
Related Article: How To Connect Power Supply To Motherboard In Easy Steps
5. Turn on the motherboard
This is where things get a bit tricky because since you have not connected the motherboard to the case yet, there is no power button.
So how are you supposed to turn on the motherboard without the power button?
The answer is that there are three ways to turn on the motherboard:
- If the motherboard has a power-on button, press it.
- Short the power-on header with a jumper or screwdriver if the motherboard doesn’t have a power-on button.
- If the motherboard doesn’t have a power-on button, connect it to the case’s power button.
Let’s examine these three methods in more detail:
The motherboard power-on button method
This is the most straightforward method. If your motherboard has a power-on button, simply press it, and the motherboard will power on. However, this feature is not available on most motherboards, and you will find it only in newer high-end motherboards.
Shorting the power-on header method
The second method is to short the power-on header with a screwdriver or jumper. This method is not as easy as the previous one, and you will need to refer to your motherboard manual to find the front panel header.
A front panel header is a group of pins that allow you to connect the power button, reset button, and LEDs to the motherboard.
Once you find it, locate the power-on header, usually labeled as “PWR_SW” or “PWRBTN.” To short it, simply take a screwdriver or a jumper and touch the two power switch pins.
This will complete the circuit, and jump start the motherboard. Be careful not to touch any other header pins cause if you do, your motherboard won’t power on.
Connecting the power button of the case
The third and final method is to connect the case’s power button to the motherboard. To do this, you should follow the same steps you did in the shorting method to find the front panel header and the power on switch.
Once you find it, connect the case’s power button cable instead of shorting the header with a screwdriver.
After connecting the power button, simply press it, and the motherboard should power on.
What to expect after you have turned on the motherboard?
As I told you should not expect to see anything happening like your computer posting or the BIOS settings. This is because you haven’t connected any other computer parts to the motherboard like the CPU, RAM, or GPU.
You should expect to see the power LED light on the motherboard lighting up, which indicates that the motherboard is receiving power, and hear beeping error codes because of the missing components.
“I did what you said, and my motherboard didn’t make any sounds or turn on LED lights.”
Ok, the first thing is to take a deep breath and not panic. You should check a few things to see what might be the problem.
1. Check if your motherboard has LED lights in the first place.
While most motherboards have some form of LEDs, not all do. So, if you don’t see any LEDs lighting up, it might be because your motherboard doesn’t have them in the first place.
First, check if the power supply unit is plugged in and turned on. I know this might sound like a dumb thing to check but trust me, it happens more often than you think.
Also, make sure that the 24-pin connector is plugged in properly. This is the main power connector, and the motherboard won’t power on if it’s not plugged in.
Then take the motherboard manual and see if there are any LED lights for troubleshooting. If there are not any, then there is not much you can do, and we will talk later about what you can do in this case.
Related Article: What Does The Red Light On Motherboard Mean & How To Fix It
2. Check if your motherboard has onboard speakers
Now that you have checked if your motherboard has onboard LEDs and the 24-pin connector is plugged in, it’s time to check if your motherboard has an integrated speaker.
Not all motherboards have onboard speakers; you should find out if yours does before moving on to the next step.
To do that, you should check your motherboard’s manual
If your motherboard doesn’t have onboard speakers, there are two solutions.
The first one is to buy a motherboard speaker and connect it to the front panel header. They are pretty cheap and easy to find.
The second solution is to use your case’s speaker by connecting its cable to the front panel header.
What to do if your motherboard doesn’t have LED lights and you can’t find a speaker?
While this is not a very common problem, it can happen. The best thing you can do in this case is to connect either a CPU fan to a fan header or the CPU fan to the CPU fan header to see if they spin.
What you are trying to accomplish by doing this is to see if the motherboard is sending power to the fan headers. If the cooling fans start spinning, it means that the motherboard is getting power and is not dead.
Of course, this doesn’t mean that your motherboard is working correctly, but it indicates that it’s not dead.
There are other ways to troubleshoot a motherboard, but they are beyond the scope of this article.
Related Article: How To Connect Extra Fans To Motherboard
How to test motherboard without CPU FAQ
Can you get into motherboard BIOS without CPU?
No, you cannot get into the BIOS without a CPU. As I told you, the motherboard won’t even POST (Power On Self Test) without a CPU, so there is no way you can get into the BIOS.
How do I start my computer without a CPU?
Your computer won’t start without a CPU. The motherboard requires a CPU to post; without it, you won’t be able to do anything. If you want to turn on your motherboard without a CPU, you can use a jumper to short the two power headers on the motherboard. While this will turn on the motherboard, you won’t be able to do anything else since there is no CPU.
Can a motherboard POST without a CPU?
No, a motherboard will not POST without a CPU. The POST is a process where the motherboard checks if all the components are working correctly.
This was a long article, but I hope you found it helpful. As you can see, there are a few ways to test if your motherboard is working properly without a CPU.
All you have to do is to follow the instructions, and you should be able to check if your motherboard is working or not.
Of course, to know exactly what is wrong with your motherboard, you will need to use a CPU and test it further.
But if you just want to know if the motherboard is receiving power and it’s not dead, then these methods should work fine.
I hope this article helped, and if it did, please consider sharing it with your friends. Thank you for reading!
Nick Ryley is a computer architect and the owner of The Pc Geekz.
His love for playing games got him interested in computers in the first place. He wanted to be able to build a gaming PC that could run all the latest games at max settings, and this has him pursuing a major in computer architecture!
He started this blog to help people out and answer some of the most common questions about computer building