Six months ago I wrote FB14122473, detailing how the built-in CDC (or FTDI) VCP serial port driver is limited to 3 Mbps or less. Thing is, there are some FTDI devices that can do 12 Mbps (maybe more), and I have devices I need to communicate with at 4 Mbps. I had to use the FTDI SDK to be able to communicate with these.
I was hoping this post might help draw attention to that bug report.