MSI Fan Diagnostic: High Idle RPM

MSI Fan Diagnostic: High Idle RPM | Generated by AI

Home 2026.07

Here’s the complete English summary of your fan diagnostic:

Fan Check Results — MSI MAG B760M Mortar + Thermalright Frozen Prism 240

Hardware Monitor Chip

Loaded NCT6687D driver (nct6683 force=1) — configured to auto-load on boot.

Current Fan Status

Channel	RPM	PWM	Notes
fan1	~1546 RPM	81/255 (31%)	Only active fan
fan2-fan10	0 RPM	various	Unconnected headers or no feedback

Temperatures (all excellent)

CPU (PECI):      35°C
PCH (Chipset):   49°C
GPU (RTX 4070):  39°C (fans stopped)
NVMe (980 1TB):  40°C
HDD (WD20EZBX):  active/idle

Key Findings

1. ⚠️ Fan runs high at idle

PWM 31% should map to ~590 RPM if linear, but you’re getting 1546 RPM
The Thermalright Prism 240 fans (max ~1850 RPM) are running at ~83% of max speed at just 31% PWM
Likely: the fan’s PWM response has a high minimum floor, OR the BIOS minimum duty cycle is set too high

2. 🔇 OS has no PWM control

PWM controller (INTC1085:00, npwm=1) shows 0/1 channels exported
BIOS is in full control of fan curves — typical for MSI boards

3. 🔊 HDD mechanical noise contributor

WD20EZBX (1.8TB, 7200 RPM) spinning drive — continuous rotation/seek noise

4. 🎯 Pump likely not reporting speed

The AIO pump is probably on the AIO_PUMP header, which reports 0 RPM to the NCT6687 chip — it’s likely running at full speed but the sensor doesn’t capture it

🛠 Recommended Fixes

Enter BIOS (Del/F2) → Hardware Monitor

1. Set AIO_PUMP header to 100% fixed (DC full speed)
   This keeps water flowing consistently regardless of CPU temp

2. Set CPU_FAN to PWM mode with a custom curve:
     30°C → 30%  (~550 RPM)
     50°C → 50%  (~920 RPM)
     70°C → 75%  (~1400 RPM)
     85°C → 100% (~1850 RPM)

For Quieter Operation

BIOS → Overclocking → CPU Lite Load: Set to Mode 5-7. This undervolts the 13900KF — minimal performance loss, 10-15°C temperature reduction.

BIOS → Tools → Custom Turbo: Set Long Duration Power Limit to 200W. This significantly reduces heat output with only ~5% performance loss in heavy workloads.

📊 Your Hardware Summary

Component	Status
CPU	i9-13900KF @ 35°C idle (powersave governor)
Motherboard	MSI MAG B760M Mortar (NCT6687D chip)
Cooler	Thermalright Frozen Prism 240 (fan1: ~1546 RPM)
GPU	RTX 4070 @ 39°C (fans stopped)
Storage	WD20EZBX 1.8TB HDD + Samsung 980 1TB NVMe
Thermal status	✅ All temperatures well within limits

Run ww linux check-fan anytime to re-check fan status and temperatures.

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