In order to decrease the download time of the tachographs remove the Detailed speed record form the downloading list.
You can do this from TachoSafe 1.0 Lite -> General settings -> Untick the Detaild speed in download options or
by unchecking from the device directly by inserting the smartcard with chipside out, press F1 then navigate with F3 to Detailed speed, press F1 to uncheck the option then F4 to Save. Now download the tachograph again.