Interupts and Context switches represent overhead and ineffeciency (in general).
The Same 15 4TB drives in a raidz3 with a hotspare (16 drives total).
Testing was just a scrub (no fresh boot). Switched between CFQ and NOOP a couple of times.
The picture generally speaks for itself, but in general I noticed a doubling of the context switches and adding 1 to the load level.
I also about a 20% increase in Interupts.