How to Identify a Dead CPU: Symptoms and Troubleshooting Guide

The CPU is generally the most durable component in a system. But there are still rare occurrences where the CPU dies.

Some will show signs like random crashes, freezing, and BSODs. While, other times the CPU may suffer some physical damage (e.g., bent pins) and can stop working abruptly.

When the CPU dies like that, use the diagnostic indicators during POST to check whether the CPU is detected or not.

Swapping the CPU for a known good one will also help you confirm whether it’s your CPU or some other component that’s dead

How to Tell if CPU Is Dead?

Diagnosing Dead CPU

A CPU that’s outright dead is easy to diagnose. Your PC will be stuck at POST as it can’t boot without a functional CPU.

At this point, use the methods shown below to confirm whether the CPU is the problem.

Debug LED


The CPU LED on the motherboard stays lit if your system can’t boot due to CPU-related problems.

These problems include general CPU issues like inadequate power or bent pins. So, check the verification section further below to make sure the CPU is actually dead.

POST Codes

Debug Port for displaying Hex codes

If you have a debug port, it’ll display different hexadecimal codes to indicate different boot problems. For CPU problems, you’ll usually see the following codes:

  • 56
  • 57
  • 58
  • 59
  • 5A
  • D0

Refer to the verification section for further steps.

Beep Codes

Motherboard Speaker

If you’ve installed a motherboard speaker, it’ll play audible beeps in the following patterns to indicate CPU problems:

  • 5 beeps
  • 7 beeps
  • 11 beeps

Refer to the verification section below for further steps.

Verifying CPU Status

As stated, the POST diagnostics will only indicate whether there are any CPU-related problems. They can’t directly tell whether the CPU is dead or not.

To verify this, test your CPU on another system, or try a known good CPU on your system. Either way, you’ll figure out whether the CPU is the problem.

Note: If this is a new build or you just upgraded your CPU, your system may need a BIOS update to be compatible with the CPU. Check your motherboard’s BIOS update changelogs to verify this.

Signs of a Dying CPU

Before CPUs completely die, they tend to show signs of degradation such as:

  • Random shutdowns
  • Freezing
  • BSODs

If your system is showing such symptoms, check for bent pins. As the CPU is still partly functional, I expect that only a few pins are bent, which you can probably repair.

If that doesn’t help and the crashes persist, at least you’ll be ready to replace the CPU when the time comes.

Mohamed SAKHRI
Mohamed SAKHRI

My name is Mohamed, and I'm the creator and editor-in-chief of Tech To Geek. Through this little blog, I share with you my passion for technology. I specialize in various operating systems such as Windows, Linux, macOS, and Android, focusing on providing practical and valuable guides.

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