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Significant 12V Rail Voltage Drop Under Load (GPU PCIe Slot & Motherboard)
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Significant 12V Rail Voltage Drop Under Load (GPU PCIe Slot & Motherboard)

By 1 Min Read


PC Specs:

  • GPU: EVGA RTX 3070 Ti FTW3 Ultra
  • Motherboard: ASRock Z490M Pro4
  • CPU: Intel Core i9-10900K
  • PSU: Corsair RM850x (2021 Model)

General Info: CPU is stock settings, GPU has the "OC" switch ticked on, for the physical switch on the card. Had system since 2021-2022. Cleaned regularly. GPU uses 2x 6+2 Pins.

The Issue

While monitoring my system under load via HWInfo64, I noticed a significant discrepancy in my +12V rail stability. Specifically, my GPU PCIe +12V Input Voltage is dropping to a minimum of 11.173V.

For context, my other 12V readings stay relatively stable:

  • Motherboard +12V Rail: Min 11.712V – 11.820V
  • GPU 8-pin #1/#2 Inputs: Min 11.637V -11.790V

Screenshot Evidence Underload

Screenshot Evidence Idle

Questions for the experts:

  1. PCIe Slot Drop: Why would the PCIe slot voltage specifically drop so much lower (11.1V) compared to the 8-pin connectors and the motherboard's own 12V reading?
  2. Hardware Risk: Is an 11.1V dip dangerous for the long-term health of the GPU or the motherboard's PCIe traces?
  3. Diagnosis: Does this look more like a failing/underpowered PSU, or an issue with the VRMs/delivery on the ASRock Z490M Pro4?