POST Code 15 - North-Bridge Memory Init

What is POST-CODE-15?

The POST-CODE-15 error is categorized as a high-severity hardware BIOS/UEFI issue that can significantly impact your PC's stability. 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. When experiencing the POST Code 15 fault, the system fails to complete the Power-On Self Test, hanging on a black screen while the debug LED or beeper shows code 15. In most diagnostic scenarios, this problem is directly triggered by incompatible RAM specifications, incorrect memory training parameters in BIOS, and uneven CPU cooler mounting pressure. To permanently resolve the POST-CODE-15 issue and prevent further system degradation, it is highly recommended to follow our step-by-step troubleshooting guide below, ensuring your hardware BIOS/UEFI components are functioning correctly.

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

  Applying the first fix (Reset BIOS to defaults by shorting CMOS pins) addresses the most common root cause of POST-CODE-15 and restores baseline functionality.

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

  If the problem persists, proceeding with the remaining steps ensures all edge cases related to BIOS memory training instability are covered.

• 3
  Update motherboard BIOS using Flashback button
• 4
  Loosen CPU cooler screws slightly and reseat CPU

Commands & Diagnostics