In at least one case (I've most clearly observed this in cheapish Android tablets): inexpensive flash storage. I've been able to observe, most obviously with m

In at least one case (I've most clearly observed this in cheapish Android tablets): inexpensive flash storage. I've been able to observe, most obviously with my first gen Nexus 7 but also with other devices, that pure CPU benchmarks are still fine, but "disk" benchmarks show terribly low (~100kbps) throughput. Lots of modern software assumes flash/SSD is fast, but inexpensive flash wears out to the point that this assumption fails. At least once I've seen a thorough wipe very temporarily restore some performance in such a case.