1. Were you using BIOS v42? Is this NUC a new revision without WHEA errors?
2. Aleutia R50 uses the same i5-6260U CPU without fan (passive cooling with only large copper block). If this NUC6i5 throttles under heavy use, then I assume a system without a fan would probably throttle more frequently. Maybe you guys could get an
Aleutia R50 (i5-6260U) for testing, and check the effectiveness of the passive cooling block?
3. Is it possible to put the M.2 SSD and 2.5" SSD in RAID0?