Ah so Unraid doesn't use R5 itself? I just thought Unraid was like an OS and it used whatever file sorting format etc you picked.
By power gating performance do you mean like SpeedStep?
Unraid doesn't use RAID in the sense you're thinking, it uses a single drive (or multiple drives) to store parity to recover from a single drive (or multiple drive) failure. More parity drives = can survive more data drives failure. so 1 Parity (1p) can support say 20 data drives and if 1 dies it's OK, no data loss. If you have 2P you can loose 2D, if you loose more D than P you still have all the data accessible on the other drives unlike R5 etc. Simply put Power Gating is intel's technology to turn off un-used cores, think 8 core CPU only powering 1 core when idle.