[Windows] NPCF Dynamic Boost targets eGPU instead of internal laptop GPU — RTX 5090 stuck at 95W with Thunderbolt eGPU

[zletpm]

RTX 5090 Laptop stuck at 95W when eGPU (RTX 5080) is connected — NPCF Dynamic Boost bug

System:

• MSI laptop, Intel Core Ultra 9 275HX
• Internal GPU: RTX 5090 Laptop GPU (24GB) — PCI bus 01:00.0, SUBSYS 14741462
• External GPU: RTX 5080 (Thunderbolt eGPU) — PCI bus 54:00.0, SUBSYS F3221569
• Driver: 32.0.15.9531 (nvpcf.sys 2026-01-13)
• Windows 11 Pro 26200
• MSI Center: Extreme Performance mode, Discrete Graphics Mode

Problem: When the RTX 5080 eGPU is connected, NPCF (nvpcf.sys) assigns Dynamic Boost to the external desktop GPU instead of the internal laptop GPU. This locks the RTX 5090 Laptop at its base TDP of 95W instead of 175W.

Testing performed:

Condition | 5090 enforced power limit -- | -- eGPU disabled in Device Manager | 175W (correct) eGPU enabled | 95W (incorrect) eGPU enabled + NPCF disabled | 95W (no Dynamic Boost at all) eGPU enabled + NPCF cycled (disable/re-enable) | 95W eGPU enabled + MSI Center profile toggled (Extreme/Balanced/ECO via WMI) | 95W nvidia-smi -pl 175 (admin) | "Changing power management limit is not supported" NVML nvmlDeviceSetPowerManagementLimit | "Not Supported"

Conclusion: NPCF is the sole source of Dynamic Boost for the laptop GPU. When two NVIDIA GPUs are present, it targets the wrong one. The desktop eGPU has its own 360W power supply and does not need Dynamic Boost.

Expected behavior: nvpcf.sys should identify the internal laptop GPU by:

• PCI bus topology (01:00.0 = internal, 54:00.0 = Thunderbolt)
• Subsystem vendor ID (1462 = MSI OEM = internal GPU)
• Or ACPI _DSM presence

and assign Dynamic Boost exclusively to the internal GPU.

Workaround: The only working workaround is disabling the eGPU in Device Manager, which defeats the purpose of having one.

This issue also affects RTX 40-series laptops — see egpu.io thread and GeForce Forums thread.

RTX 5090 Laptop stuck at 95W when eGPU (RTX 5080) is connected — NPCF Dynamic Boost bug

System:

MSI laptop, Intel Core Ultra 9 275HX
Internal GPU: RTX 5090 Laptop GPU (24GB) — PCI bus 01:00.0, SUBSYS 14741462
External GPU: RTX 5080 (Thunderbolt eGPU) — PCI bus 54:00.0, SUBSYS F3221569
Driver: 32.0.15.9531 (nvpcf.sys 2026-01-13)
Windows 11 Pro 26200
MSI Center: Extreme Performance mode, Discrete Graphics Mode
Problem:
When the RTX 5080 eGPU is connected, NPCF (nvpcf.sys) assigns Dynamic Boost to the external desktop GPU instead of the internal laptop GPU. This locks the RTX 5090 Laptop at its base TDP of 95W instead of 175W.

Testing performed:

Condition 5090 enforced power limit
eGPU disabled in Device Manager 175W (correct)
eGPU enabled 95W (incorrect)
eGPU enabled + NPCF disabled 95W (no Dynamic Boost at all)
eGPU enabled + NPCF cycled (disable/re-enable) 95W
eGPU enabled + MSI Center profile toggled (Extreme/Balanced/ECO via WMI) 95W
nvidia-smi -pl 175 (admin) "Changing power management limit is not supported"
NVML nvmlDeviceSetPowerManagementLimit "Not Supported"
Conclusion:
NPCF is the sole source of Dynamic Boost for the laptop GPU. When two NVIDIA GPUs are present, it targets the wrong one. The desktop eGPU has its own 360W power supply and does not need Dynamic Boost.

Expected behavior:
nvpcf.sys should identify the internal laptop GPU by:

PCI bus topology (01:00.0 = internal, 54:00.0 = Thunderbolt)
Subsystem vendor ID (1462 = MSI OEM = internal GPU)
Or ACPI _DSM presence
and assign Dynamic Boost exclusively to the internal GPU.

Workaround:
The only working workaround is disabling the eGPU in Device Manager, which defeats the purpose of having one.

This issue also affects RTX 40-series laptops — see egpu.io thread and GeForce Forums thread.