High IOWait -> DSM nearly unusable

Hello,

i recently installed DSM 6 via juns loader but I have some issues with it. The system I run it on is a ASRock N3050M with 2 2TB harddrives from Seagate and the loader is on a Intenso Rainbow Line USB Stick. As mentioned in the title the system is permanently having 20-40% IOWait, most time even more up to 100%. Also one drive is kept at a high workload without a reason I can see. The other drive is just sitting there doing nothing. This even happened before I initialized the disks.

Can you help me with that?

Kind regards,

Paktosan