POST Code 15 - North-Bridge Memory Init

What is POST-CODE-15?

POST-CODE-15 shows up as a high-severity hardware BIOS/UEFI fault. Motherboard POST code 15 indicates a failure during early North-Bridge memory initialization. Commonly caused by memory compatibility issues, training timeouts on high-frequency DDR4/DDR5 sticks, or bent CPU socket pins. This can also stem from incompatible RAM specifications or speed profiles. The steps below are ordered to resolve this efficiently.

Common Causes

• Incompatible RAM specifications or speed profiles
• Incorrect memory voltage parameters in BIOS NVRAM
• Bent CPU socket pins (uneven memory channel contact)
• Uneven CPU cooler mounting pressure (warped board)

Step-by-Step Fix Guide

• 1
  Reset BIOS to defaults by shorting CMOS pins

  As a first move, Reset BIOS to defaults by shorting CMOS pins handles the most common scenario behind POST-CODE-15.

• 2
  Use a single RAM stick in slot A2 to bypass boot check

  If the problem isn't fully resolved yet, the remaining steps rule out the less frequent BIOS memory training instability triggers.

• 3
  Update motherboard BIOS using Flashback button

  "Update motherboard BIOS using Flashback button" targets incorrect memory voltage parameters in BIOS NVRAM, one of the documented causes of POST-CODE-15.

• 4
  Loosen CPU cooler screws slightly and reseat CPU

  If earlier steps didn't help, "Loosen CPU cooler screws slightly and reseat CPU" directly addresses uneven CPU cooler mounting pressure (warped board).

Commands & Diagnostics

Frequently Asked Questions