USB 1.1 was 12 Mbps, USB 2.0 was 240 Mbps but was update to 480 Mbps which is what I presume they mean by slow, the slow will be 240.
Read this click here
This is my guess by the way I do not know if this is what they mean.
If you have USB 2.0 then its probably the faster USB of 480 I don't know how to test this for sure, but would be fairly sure this is what you have.
If it says enhanced under USB controllers in device manager then you have USB 2.0.