Can You Boot a Motherboard Without a CPU?

If you are planning to build your first PC or is checking whether or not your motherboard can turn on without a CPU, you are here at the right place. Today, in this guide, we are going to talk about all the measures through which you will be able to boot your motherboard without a CPU. More often, you are likely to search for this answer for the fact that your motherboard has not arrived yet!

Well, you must know that it is not possible to turn on your motherboard without the CPU. Utmost, you can just spin the fan for a couple of seconds but not more than that, and that too, with some of the motherboards. Therefore, it is quite clear that any testing which you do with your Motherboard, but without the Central Processing Unit is not justified.

Will Your Motherboard Turn On Without the CPU?

Your motherboard won’t be able to take a boot up if you do not have a CPU. Without the presence of a CPU, you cannot expect your motherboard to turn on. Also, you shall not be able to conduct a Power On Self Test or POST and verify if your mouse, keyboard or any other hardware device is connected to the motherboard. Consequently, it won’t be possible for you to figure out if all of those devices are actually working properly or not!

To your surprise, you might find that a few motherboards will turn on their fans initially but that won’t last for more than a few milliseconds. As soon as your motherboard would detect that you are not having a CPU connected to your system, it will automatically turn off. On top of that, if you are planning to enter the BIOS mode, you may or may not be able to do so! While very rare motherboards would be able to support this, most of them won’t!

How does BIOS flashback function?

If your motherboard is having the feature of BIOS flashback, it will actually be able to turn on the power on the board and thus, update the BIOS. However, you would require 24 pins alongside the EPS cables connected to your device. If all the things are in place, it won’t require a CPU or a RAM further! Do not worry, none of the other parts of your system would get affected while you turn it on.


Your PC will turn on without your CPU only when there is an incompatibility between your CPU and your motherboard. In such a scenario, the best possible thing that you can probably do is to replace either your CPU or your motherboard. This is because it is something very abnormal and you must also check that your motherboard socket isn’t having any physical damage.

Nonetheless, you need to verify if the CPU PWR is appropriately connected to your mainboard headers. You can even get a PSU borrowed from someone you know to see if you can fix the trouble, as it would give you a clarity that nothing is wrong with the power connection. If all the aforementioned issues aren’t working with your PC, the last thing that you can possibly do is change either the CPU or the motherboard.

A step by step guide to test your motherboard without the CPU

You can even check the functionality of your motherboard without having a CPU provided that all the power supply delivery points are in place. Note that while you will be conducting this experiment, you actually be able to turn on your PC but rather you can witness a few LED flashes or maybe a series of beeping sounds, being exhibited from your motherboard. To avail an additional precautionary measure, you shall place the motherboard on an anti-static foam instead of any conductive or metallic surface.

Once done, you can now plug in the power connectors – the 8 pin CPU connector or the 24 pin motherboard power connector. Next, connect the power supply to the wall socket. Lastly, find the Power switch pins present on the Front panel connectors. Next, figure out the power switch cables and ensure that they are appropriately connected to the pins. After everything is done properly, your last to-do job is to press the button on the case and then turn on the power on the motherboard.

Frequently Asked Questions

Can you turn on turn on the motherboard without a GPU?

You can turn on the motherboard without a GPU. You will neither have to worry about getting any of your components damaged while you do this! However, you would hear an error beep code and your PC will turn off in sometime in case you are attempting for this!

What is the difference between an Integrated graphics and a GPU?

Both are just the same! The major difference between the integrated graphics and that of the external GPUs is that the former is built into the processor. As a result, it does not use any memory bank separately. It does only make use of the shared memory with the GPU.

Is BIOS using the RAM?

The BIOS old versions execute directly from the flash chip but the ones from the second or that of the third generation copy the BIOS from the processor cache and further to that of the RAM.

Will you be able to check the BIOs without the CPU?

If you do not have the CPU processor or the memory, you will not be able to do anything. On the contrary, if you are owning a motherboard that uses the BIOS flashback, you can easily choose to update it or flash the BIOS.

Why is the motherboard not getting the power?

The trouble is more likely with that of the CMOS battery if it isn’t receiving any power. You would probably be facing this issue if you have got an old PC which is in use for a long span now, or may be, it’s high time that you should replace the CMOS battery.

How to turn on a power supply?

Just try to locate the black and the green wire sockets on your 20 – 24 pin connector and then insert a paperclip into the same to turn on the power supply without the presence of a motherboard.

How to know that your CPU is dead?

You may consider your CPU to be dead if you are not able to POST on it. The general DOA period lies somewhere between 90 to 120 days depending on the vendor you got it from!

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