There is unpredictablilty in SSDs however, its most like whether an IOP will take 1 ns or 1 ms, instead of 10 ms, or 100 ms with an HD.<p>The variability is an order of magnitude greater but the worst case is an is several orders of magnitude better. Quite simply no one cares that you might get 10,000 IOPS or 200,000 IOPS from an SSD when all you&#x27;re going to get from a 15K drive is 500 IOPS