HDTune tests a similar level of features as compared with HDTach, but with a different access pattern. Thus provides us with an additional set of benchmark numbers to compare between storage configurations. Here we can get the minimum, maximum and average transfer rates as well as the burst rates and access times. CPU utilization has proven negligible with modern processing horsepower, and is no longer included.
HDTune's burst test gives inconsistent results. Posted here for information only.
This is about as clear of a spread as you can get for sequential read speeds. There is a clear line of distinction between 3Gb/sec and 6Gb/sec units. The Samsung 840 Pro actually gives great figures for a consumer drive.
All SSDs have near negligible access times when compared to the HDD.