@matrix Thats not as uncommon as you think. Thats the whole reason multiple runs are done on benchmarks... Keep in mind there is disk level caches, system level caches, as well as other applications you may have running as well (or even system level processes).
@freemo I know, but when I benchmarked the same drives alone, the difference between runs was like +-5MB. I didn't expect RAID to hit so much.