[selder]

Indeed, with Q-fan disabled all fans connected to the motherboard should always run at full RPM.

I can clearly see the RPMs drop from ~2200 to ~1100 in speedfan, lavalys Everest and other tools, and I don't know where this comes from.

~1200 RPM is sufficient to cool the CPU, it's idling at 17°C, (core 1 at 27°C, core 2 at 19°C - that's something else I'll have to investigate, why is this difference so big?)

I will do the following test: I'll install the Intel Stock CPU cooler, and look what his RPM will do. If they "fluctuate" too, then there is a problemen with the mainboard, if this is stable, then there must be a problem with the Shuriken...