It must be noted that many companies did shun from putting more than a couple of ports on their cards simply because it is rather tough to transfer such a huge amount of data at x2, what more x4. Heck, even motherboard manufacturers did need to make their own set of adjustments, where among them include tapping into Northbridge, Southbridge and PCI data lanes so that there is enough space for a huge amount of data to be transferred via USB 3.0.
I am not quite sure what kind of magic wand or pixie dust did Buffalo sprinkle over their latest release, but somehow they managed to tweak their own drivers to urge a few more MB/s out of USB 2.0 connectivity.