I can only refer to the technical data:
- According to the specifications of the Dark Rock Slim, the fan does not reach over the RAM slots.
-> https://www.bequiet.com/en... "Due to its compact construction no memory slots are blocked."
-> According to this, the height of the RAM is not a problem.
- The attachment of the fan to the motherboard also fits.

To the Boad:
- Not all external HDDs supplied via USB are recognised if they are already connected before booting.
- Before saving an image of C:\ as a backup on an external HDD, e.g. via Macrium Reflect, check whether the external HDD is recognised if it is already connected before booting. If not, the image will not be found when you try to restore it via Macrium Reflect.
- An external 500 GB Samsung HDD is not recognised by me. However, it is recognised if it is plugged in when the PC is booted.

Good luck