The USB connection is limited by the hardware to much less than the theoretical maximum of USB2.0, but various inefficiencies in firmware also reduce the speed. One of the most significant problems is remedied by the [U] USBAccelerator firmware patch which speeds up downloads from the Toppy enormously (note that this also requires use an updated .dll on the PC, or compatible tools). In a similar way, the [Uu] USBUpload firmware patch can help improve upload speed to the Toppy.
Other factors that can affect the USB speed is the quality and length of the cable being used. If possible, try different cables to help diagnose this, and avoid very long cables unless they are good quality and "active" (powered).
When using Altair software to transfer files, it has a faster "Turbo" mode. This mode disables the remote control; if a programme or recording is running it will continue, but cannot be changed until the transfer completes.