Troubleshooting: Two i5 9400F Processors Fail to Function on the Same Motherboard Despite Listing and Up-to-Date BIOS

Troubleshooting Boot Issues with the i5 9400F and AsRock B365M Pro4 Motherboard

Introduction

If you’ve recently faced challenges getting your new build to boot, especially with an i5 9400F processor paired with an AsRock B365M Pro4 motherboard, you’re not alone. Even though the i5 9400F is listed as compatible with this motherboard, some users are reporting persistent boot issues. Here’s a closer look at the situation and some potential solutions that might help.

Background of the Issue

Recently, I assisted a friend who was assembling a new PC. Unfortunately, when it came time to power the system on, it simply wouldn’t boot. After some investigation, it became apparent that the i5 9400F processor was not working with the AsRock B365M Pro4 motherboard due to an outdated BIOS version.

To resolve this, I temporarily swapped in my i7 8700K, which allowed me to successfully update the BIOS to the latest version (P4.40). You can verify the compatibility of the motherboard and the CPU directly on the AsRock compatibility page.

The Ongoing Problem

Despite the BIOS being updated to the most current version, we are still experiencing boot failures with not one, but two separate i5 9400F processors. This situation has been quite perplexing, especially given that the compatibility chart explicitly states that these processors should work seamlessly with the motherboard.

Seeking Solutions

I’m reaching out to the community to see if anyone has encountered a similar issue or has any suggestions for troubleshooting. Here are a few ideas that might be worth considering:

Check Power Supply Connections: Ensure that all power connections, including the 24-pin motherboard connector and the CPU power connector, are securely attached.
Inspect RAM Compatibility: Double-check that the RAM modules are compatible with both the motherboard and the CPU. Sometimes, boot issues can stem from incompatible or improperly seated RAM.
Test with Different Components: If possible, try testing the i5 9400F processors in another compatible motherboard to verify if the issue lies with the processors or the original motherboard.
Clear CMOS: Resetting the BIOS settings by clearing the CMOS may help to resolve any conflicts that could be preventing booting.
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