NAS crashes on large file copy

Hi!

I recently discovered that my Reaynas 102 does not seem to handle moving files very well. If I try to move a ~200GB folder from one share to another on the same NAS, it eventually freezes up and a complete hard reboot (unplugging and replugging the power cord) is the only thing that will get it back up and running again. Before the freeze, I run into "unspecified network errors" from Windows.

I'm well aware that this model by no means is for "heavy duty" use, but surely it should be able to handle simple file moving?

What I have tried to far is to give the unit a thorough cleaning with compressed air. This brought cpu temp down from ~68c to ~60c, and now it seems to handle things better, so maybe it's a temperature issue?

If so, I was wondering if there's a noob-friendly way to make the fan a bit more agressive? Mine seems to always hover around ~800RPM no matter what. And I very much prefer stable operation over silence.

Any help appreciated.