Windows PC won't boot when GPU is plugged in

Some users reported that their Windows 11/10 computer won’t start when they connect an external GPU. There can be many causes of this issue, such as an insufficient power supply to the GPU, a faulty GPU, a faulty GPU slot, etc. If your PC won’t boot when the GPU is plugged in, the solutions explained in this article will help you.

PC won’t boot when the GPU is plugged in

Use these fixes if your Windows PC won’t boot when the GPU is plugged in:

Compatibility issues
Reseat the GPU
Check the LED indication on your motherboard and GPU
Clear CMOS
Change the PCIex16 slot configuration in BIOS
Update BIOS
Test the GPU on another working computer

All these fixes are explained in detail below:

1] Compatibility issues

If your GPU is not compatible with your motherboard, you will experience boot issues. If you have purchased the new GPU, check its compatibility with your motherboard. Probably, you have ordered the incorrect GPU. If the GPU is compatible, use other fixes.

2] Reseat the GPU

Probably you have not seated the GPU properly. Reseat it carefully and see if your computer starts this time. Also, verify that you are installing the GPU in the correct PCIe slot. If your motherboard has more than one PCIe slot, you can try installing the GPU in other available slots.

If the problem has started occurring after installing a new PSU, you might be using the wrong cables. Use the same cables that come with the PSU.

3] Check the LED indication on your motherboard and GPU

Every motherboard has LED indicators for different hardware problems. These LEDs turn ON when your motherboard detects a hardware or boot issue. A specific LED indicator turns on to indicate the problem with the respective hardware. For example, ASUS motherboards have these LED indicators: CPU, DRAM, VGA, and Boot. If the VGA indicator turns ON, it means that there is an issue with the graphics card.

Check if any LED lights turn ON on your motherboard. If yes, troubleshoot it accordingly. Refer to your motherboard’s user manual for more information on LED indicators. Also, check if the LED on your dedicated graphics card turns ON. A red light on the GPU indicates that the GPU is not getting enough power. In such a case, you need to replace your PSU.

4] Clear CMOS

If the issue persists, clear CMOS. This action will also reset your BIOS settings to the default. Use these steps:

Open your computer case and locate the CMOS battery.
Remove the battery from its slot and wait for a few minutes.
Reinsert the battery into the slot with the right polarity.

Now, check if you can turn on your PC.

5] Change the PCIex16 slot configuration in BIOS

The PCIe slot configuration setting in BIOS allows you to change the PCIe generation. By default, it is set to Auto. You can change this from Auto to a specific PCIe generation in certain cases. For example, if you have a newer motherboard with the latest generation PCIe slots but are using an older graphics card or an older PCIe Riser cable, you can manually set the PCIe version to an earlier generation, such as PCIe x16 Gen 3, for improved compatibility.

Different motherboards have different settings to change this option. Refer to your motherboard user manual for the steps to change this setting. In most cases, setting it to Gen 3 resolves the issue.

If you cannot boot into BIOS, remove your graphics card, then start your computer with the integrated GPU.

6] Update BIOS

If the problem persists, update the BIOS to the latest version. Updating the BIOS will improve the system stability and hardware compatibility. Disconnect the dedicated GPU and boot your system with the integrated graphics. Now, visit the official website of your computer manufacturer and download the most recent version of your system BIOS. Run the file to update your BIOS.

7] Test the GPU on another working computer

If you still cannot boot your computer by plugging in the dedicated GPU, the problem may be with the dedicated graphics card or your PSU. To confirm this, connect your GPU to another working computer that the GPU is compatible with. If the computer boots, your GPU is not faulty.

The problem may also be with the Power Supply Unit. The PSU might not be able to provide the required power to the GPU. At this point, you need professional assistance.

Can a GPU prevent a PC from booting?

Yes, a faulty graphics card can prevent a PC from booting. Boot issues are one of the symptoms of a graphics card failure. Other symptoms of a faulty graphics card include frequent graphics glitches, strange noise from the GPU fan, a continuous drop in FPS, especially when gaming, etc.

Is the red light on a motherboard bad?

Yes, a red light on a motherboard is bad. Motherboards often feature LED indicators to alert users to potential hardware issues. Motherboards from different brands may have different-colored LEDs for the same hardware issue. Usually, the red light on a motherboard indicates an issue with the CPU.