Hardware Discussion

CW56-58 (R5-5500U): CPU blower rattles at low RPM, completely silent when the unit is upsi

2026-08-24 07:24:23
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1 Comments

Hello,


I have a CW56-58 with AMD Ryzen 5 5500U, BIOS 0.33 (2024-03-25), bought directly from the CWWK store in February (order CW6221). It runs Proxmox VE 24/7 as a home server. I have one fault to report, one question about the 8010 fan, and I also want to share what the Pc Health Status fan registers actually mean, because I could not find that documented anywhere.


1. CPU blower noise depends on the physical orientation of the machine


The CPU blower makes a rattling / resonance noise. What is unusual is that it depends on the orientation of the case and on fan speed, not on temperature.


If I turn the whole machine upside down, the noise disappears completely and immediately. If I put it back in the normal position, the noise returns. This is fully repeatable.


I believe the explanation is this. The blower is mounted with a vertical axis, so gravity acts along the shaft. In the normal position the rotor hangs downward, and if the bearing has developed too much axial clearance the rotor sits at the wrong end of its travel and rattles. Turned upside down, gravity pushes the rotor back into its correct position and the fan is silent. This also explains the speed dependence: at high RPM the impeller generates enough axial thrust to lift the rotor back into position by itself.


Measured against the fan curve: below roughly 80% PWM duty it is noisy, above roughly 80% (3300+ RPM) it is silent. With the stock curve it was worst at idle, because the fan was switching on and off continuously.


A fan in good condition should not change its noise when the machine is rotated, so I believe the bearing is worn. I already tried lubricating it, which helped only briefly.


My question: can I obtain a replacement CPU blower / cooler fan assembly? I can install it myself and I do not need to return the machine.


2. My unit has no bottom 8010 fan - which variant fits?


The bottom fan position is empty on my unit. Without it there is no airflow at all across the M.2 SSDs, and my two NVMe drives sat at 65 C and 70 C while completely idle. After fixing the BIOS fan curve they are now 44 C and 49 C, so the blower does help, but this machine clearly wants the bottom fan fitted.


The shop lists "Mini PC 8010 Fan" with three options: USB fan, Small 4PIN fan, Large 4pin fan. Which one fits the CW56-58 system fan header? Is the connection cable included? And are longer screws needed - one review says the supplied 10 mm screws are too short for this case.


3. What the Pc Health Status fan registers actually mean


The register layout matches ITE SmartGuardian, and the Linux it87 driver documents it as follows.


Fan Off (0x68 / 0x70) is the temperature below which the fan stops. Fan Start (0x69 / 0x71) is the temperature at which it starts. TFull Speed (0x6A / 0x72) is the temperature at which duty is forced to 100%. Start PWM (0x6B / 0x73) is the starting duty on a 0 to 127 scale. Automatic Mode Control (0x6C / 0x74) is NOT a mode selector - it is the PWM slope, in units of 1/8 PWM per degree C. Delta Temperature (0x6D / 0x75) is hysteresis.


So the curve is: duty = Start PWM + (temperature - Fan Start) x slope/8, and 127 once the temperature reaches TFull Speed.


One point that may help anyone with high NVMe temperatures. The stock values are Fan Off 50 and Fan Start 51, but this machine idles at about 52 C. The fan therefore switches on and off continuously all day, which is noisy and is very hard on the bearing - I suspect this is why mine wore out. Changing Fan Off to 30 and Fan Start to 31 makes the fan run continuously instead of cycling, and that alone dropped my SSD temperatures by about 20 C.


Thank you.

    paolocalviAuthor
    2026-08-24 16:04:48

    Follow-up to my earlier post about the CPU blower rattling on the CW56-58 (R5-5500U, BIOS 0.33, order CW6221). Wanted to share how this developed, since it may help others with the same symptom and it might be useful feedback for CWWK on future revisions.


    Since posting I ran a clean test: left the unit upside down overnight under normal load, completely silent the entire time. Flipped it back to the normal orientation, and the rattle returned within seconds - not gradually, immediately, at the exact moment of rotation. This rules out dust, thermal drift, or anything that would build up over time. The fault is tied purely to orientation, and it is fully repeatable in both directions.


    The explanation is simple. The blower has a vertical shaft, so gravity constantly loads one thrust face of the bearing. In the normal orientation the rotor sags onto that same contact point on every start/stop cycle, and once the bearing has enough wear it rattles there. Flipped, gravity loads the opposite face, which is far less worn, so the fan is silent.


    CWWK support has been responsive and offered to send a replacement CPU blower/cooler kit at no charge, plus an optional side-panel cover with two extra fans for additional cooling. I appreciate that and it is on the way.


    That said, I plan to keep running the unit upside down permanently even after the new blower arrives, not just as a workaround. A brand-new blower in the same vertical-shaft mounting will develop the identical wear pattern eventually, just later - the design itself guarantees that one thrust face gets loaded every single cycle. Running it in the orientation that does not fight gravity is a legitimate long-term choice, not a temporary fix. For anyone doing the same: four ~1 cm rubber feet on what is now the top (the intake side facing down) give the blower enough clearance to breathe, and it changes nothing else about function or thermals.


    If there is a lesson worth passing along for future chassis or fan-mount revisions, it is this: a vertical-axis fan bearing takes a one-directional gravity load on every start/stop cycle for the life of the product. Either mount the fan shaft horizontally, or spec a bearing designed to tolerate axial gravity loading in that orientation. Don't fight gravity - design around it.


    Hope this saves someone else the troubleshooting time.


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