I have an Asus PN50 mini-PC, which is essentially built from laptop components. Unfortunately, the fans are way too loud for my taste even in quiet mode. The max fan speed is 7200 RPM and the fan noise is acceptable only up to about 50-60% duty cycle, which is exceeded above 50-60 °C. I would like to stick with 3000-4000 RPM up to 70-80 °C instead. Unfortunately, custom fan curves are not supported by the BIOS and there is no known way to override the fan speeds from software either.
I was wondering whether it would be possible to replace the fan with another model that has a lower max RPM. However, it seems that unlike PC fans, laptop fans are hugely varied and lack detailed specifications. The fan in the mini-PC is a Sunon EG60070S1-C200-S9A 5V 1.96W fan but I have trouble looking for possible replacements. By pure chance I stumbled upon the SUNON MG75090V1-C200-S9A 5V 0.31A fan which seems to have an identical physical layout and based on its 5V × 0.31A = 1.55W power draw it may be lower RPM (or simply a smaller fan). However, I am not sure whether its dimensions and the placement of the screw holes really match those of the original fans or just look similar.
Could someone familiar with laptop fans please share their opinion about how interchangeable different laptop fan models are, what the best strategy may be to search for fitting replacements and where to look up detailed laptop fan specifications?