USB 2.0 connectivity exceeding the theoretical limit of 35 MB/s - how come?

[m654321]

Hello m654321,
this says maximum 60MB/s - https://en.wikipedia.org/wiki/USB#USB_2.0

Many thanks bitsnpcs - this wiki link was really interesting - not sure where exactly where I got the 35MB/s limit for USB 2.0 connectivity from!  : 

So, according to this link, 60MB/s does appear to be possible for USB 2.0 (designated High Speed, 2000), which explains what I observed.  Interestingly too, is the info it gives for USB 3.0 (designated Superspeed, 2008), where it says it's realistic to get 400MB/s or more.

Based on personal observation, there would appear to be two other factors affecting USB connectivity: CPU speed (e.g. i3 vs. i7) & Drive characteristics (e.g. SSD vs. HDD, HDD rpm) - these were my finds:

1. CPU - when transferring data from an internal SSD to and external 10TB HDD (7200 rpm), USB 3.0 connectivity rates averaged around 80 MB/s for an i3-3110M machine compared to 110 MB/s for an i7-4710HQ one.

2. Drive Characteristics - as expected there  seem to be huge differences in USB 3.0 connectivity rates between an SSD-to-SSD system, compared to an SSD-to-HDD one. For example with a i7-4710HQ machine, I would get rates of 300-400 MB/s (peaking at 400-500 MB/s), when copying from an internal SSD to an external one. This would drop to around 110 MB/s (peaking at 120-130 MB/s), when copying from an internal SSD to an external 7200 rpm HDD, as mentioned above.

Again, there would of course be differences between copying to an 5400 rpm HDD vs. a 7200 one, but I haven't done any observations to quantify this.

Many thanks again bitsnpcs & please excuse the delay in replying to you - I've just been tied up with other things recently ...