I think one of the issues may be that average throughput over USB varies widely, and is almost never close to maximum. In fact I believe the moment you plug any other USB devices into ports which are shared by common hardware components of a given PC, you are then dividing the max potential throughput by the number of connected devices.
I see the difference between max possible and average throughput quite a bit with things like large transfers over USB 2 and 3 hard drives. A lot of different factors affects the real-time speed including how fast the data is being served on one end of the wire, how fast its being received on the other end of the wire, the polling frequency of every moving part in between and so forth. If you monitor performance of transfers in real-time, you sometimes see bursts of speed that approach theoretical max, but not consistently.
So I can't prove it, but I'm guessing 6 total channels is really pressing USB 1.1's luck.
|