The performance of hard disks has only slightly evolved over the last couple of years

Tom's Hardware  amuses themselves by comparing the performances of two discs 2,5" spinning at 7200 rpm. Rather than to compare two models being currently marketed, they compared two discs marketed with 2 years difference, the Hitachi 7K200 and a 7K500 in order to know if it was a beneficial to choose a more recent disc to gain in performances.
The result is in conformity with the development undertaken by all manufacturers of hard drives with platters. The new products have a higher capacity, they consume a little bit less, but overall the performances has only very slightly evolved. For daily use, one can not await a whiplash in performance with such a change of disc. The gains will only be visible to those with a stop watch in hand.
For these manufacturers of discs, it is much easier, all at least for the moment, to optimize the proven mechanics and to use denser platters rather than to start out trying to increase the speed of rotation of the platters that is very expensive in term of energy expenditure and reliability of mechanics. For many long years that the speed has been blocked at 7200 rpm, and only certain professional discs or semi pro as Raptor from Western Digital goes further. Without increasing the speed of rotation, it is practically impossible to improve access times significantly, and for daily use this is what gives the best feeling of performances well before improved data flows. Today the only means of gaining on this point is to pass to the SSD, which is still very expensive and has also reached an impasse concerning capacity.