Our desktop support techs at my office sometime see USB3 compatibility speed issues mostly related to the chipset that's being used in the controller. We have a number of external Drobo USB3 raid boxes for media work. Mine works at USB3 transfer speeds on my workstation. I tend to customize my own stock DELL PC and Macs myself at work - stretching the hardware capability limits. But a few other desktop manufacturers we have don't seem to be able achieve faster than USB2 transfer speeds on a consistent basis.