The fan indeed is quite bad. However, you can ‘easily’ change that fan for a quiet fan 
There is one downside though; you will need to order a new fan (very easy), then remove the old fan (easy), then use a soldering iron to remove the wires (with connector) from the old fan and the new fan, and resolder the ‘old’ wires (with connector) to the new fan (this can be quite hard to do, and requires skills/experience), before mounting the new fan into the minibook.
This is because the Minibook has a custom connector, and when you order a replacement fan it does come with the wrong (and useless) connector.
useful links: