ProDesk 600 G5 CPU Fan control

msssm · ‎06-14-2025

ProDesk 600 G5 with i7-9700.

How can I change the CPU fan control? It seems to be integrated and not visible to the system? At least Linux lm-sensors doesn't see any fan or rpm value.

The problem is, the fan is quite sensitive and turns to max even around 78°C package temperature and above. On idle it's quiet but for every very simple load on single cores the fan turns up to max. It is very noisy.

Hardware is absolute clean and freshly mounted with thermal paste. The CPU keeps cool, but the fan seems to be to aggressive. All older HP desktops I owned like EliteDesk 800 G1 were absolutely quiet, but this here is the most noisy.

Back to linux. I don't see anything in sensors or fancontrol. I would try intel-undervolt now, but actually 78°C is not much and I never see higher temperatures than about 80°C looking at:

intel-undervolt measure

NonSequitur777 · ‎06-15-2025

@msssm,

Welcome to our HP Community forum!

Why Fan Control Doesn’t Work in Linux:

HP business desktops (such as the ProDesk line) don’t expose fan RPM or control via standard ACPI or SMBus interfaces, which means tools like lm-sensors or fancontrol won’t detect the fan or its speed sensors.
Fan profiles are hardcoded into the BIOS/EC firmware, and not user-configurable.
BIOS Setup (F10) for this model typically lacks advanced thermal or performance tuning options.

Why the Fan Seems Overly Aggressive:

HP likely uses a conservative thermal policy prioritizing hardware longevity and assumes office use cases (low background noise).
The i7-9700, although within TDP limits, can still produce high transient heat spikes on 1–2 cores, triggering short-term fan bursts.
Even small workloads that push temps into the upper 70s °C will often result in full-speed fan spin-up on these models.

User-Verified Workarounds & Recommendations:

Undervolting (as you’re considering):
- Using intel-undervolt is a smart workaround and if you can get it to work, can reduce package temperatures by 5–15°C depending on the chip.
- You may also see less frequent fan spin-ups at the same workload if temps remain under HP’s internal ramp-up threshold (~75–77°C).
Replace the Stock Fan with a High-Quality PWM Fan:
- HP uses a proprietary 4-pin PWM fan with standard pinout, so you can try replacing it with a quieter model like:
  - Noctua NF-A9 PWM (92mm) — highly recommended.
  - Arctic F9 PWM PST — cheaper alternative.
- You’ll need to ensure:
  - Same connector (PWM 4-pin)
  - Similar CFM and static pressure (HP’s default fans are tuned for the small airflow in the SFF chassis)
- While the new fan still responds to HP’s fan curve, it may do so more quietly, reducing acoustic annoyance.
BIOS Update (Slim Hope):
- Occasionally, HP BIOS updates revise thermal behavior.
- It’s worth checking if a new BIOS version is available that may tone down the fan ramp.
Thermal Padding & Case Ventilation Mods:
- Improving your overall case airflow (adding one or more cooling fans or vent mods) helps reduce chassis heat buildup, which is often interpreted by the thermal sensor as justification for fan ramping.

What Doesn’t Work:

fancontrol, pwmconfig, or lm-sensors adjustments (not supported by BIOS/EC).
Disabling fan control in BIOS — not an option.
Windows tools like SpeedFan — these also don’t work with HP EC firmware.

Caution:

Avoid using third-party EC override tools or modded BIOS in HP business desktops — HP locks firmware signatures tightly, and such efforts may brick the system or prevent BIOS updates and support.

Conclusion:

The aggressive fan ramp-up behavior on your HP ProDesk 600 G5 is unfortunately a limitation of HP's firmware, which doesn’t expose fan control to the OS. Your best options are to try t undervolt the CPU using intel-undervolt and consider replacing the stock fan with a quieter PWM fan like the Noctua NF-A9. These changes won’t give you manual fan control but can reduce how loud it gets under light workloads.

Kind Regards,

NonSequitur777