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June 3rd, 2025 07:49
XPS 8950, RTX 5080 FE, 1350W PSU, POST issues
Hi all,
Last year I upgraded my Dell XPS 8950 with a Dell 1350W PSU. The PSU is the only one which has 4x8 pin (8=6+2). The PSU also has a MB 12 pin connector which fits well in the MB 10 pin slot. Some say the 2 extra pins that hang are 12v and GND.
Yesterday I got my Nvidia RTX 5080 Founders Edition, connected it to the XPS and I noticed POST issues.
With the RTX GPU connected, the PC does not POST if Display Port is connected to the RTX GPU. The power button error code is: “Power Rail Failure: EC ran into power sequencing failure (3 amber 5 white)”
If I manage to POST, in Windows 11 everything goes well, no issues. But when the PC enters sleep mode, it does not wake up and shows the same “Power Rail” error code or “CPU configuration or CPU failure”.
All cables fit well, never had issues.
Is this a PSU / XPS issue or a Windows 11 UEFI issues?
Element115s4
2 Intern
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June 3rd, 2025 11:29
I doubt that is a supported XPS 8950 PS.
Isn't the max a 1000W which is plenty for the 5080?
Good GPU choice though.
ovdell
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June 3rd, 2025 13:38
The 1350w psu works just fine. I used it for 2 years with my old rtx 3070.
I think this is just a limitation from dell.
thoughts?
Element115s4
2 Intern
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284 Posts
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June 3rd, 2025 20:16
From Copilot:
Reset Real-Time Clock (RTC)
Performing an RTC reset can sometimes resolve the issue.
Ensure that the PSU is functioning correctly by performing a Built-In Self-Test (BIST) if available.
Potential Solutions
Replace Motherboard
If the above steps do not resolve the issue, you may need to replace the motherboard. This is often necessary as power rail failures are typically related to motherboard issues
Element115s4
2 Intern
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284 Posts
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June 3rd, 2025 20:33
In addition, replace the MB battery.