Power Sag System Freeze / Lockup

What is PSU_POWER_SAG_FREEZE?

The power supply unit voltage rails drop below the minimum safety threshold under sudden current transitions (transient power spikes), causing the CPU or GPU to freeze instantly without a Blue Screen.

Common Causes

• Degraded power supply capacitors
• High GPU transient spikes (e.g. RTX 30/40 series spikes)
• Loose ATX power connectors

Step-by-Step Fix Guide

• 1
  Ensure separate dedicated PCIe power cables are plugged into the GPU

  Running dedicated cables prevents high current drops across a single 12V rail path.

• 2
  Replace the power supply unit with a high-quality unit containing robust capacitors

  PSU replacement is eventually required if output capacitors have degraded.