1st time Scanning and Synchronization is always the slowest , afterwards synchronization will be faster
Scanning speed depends on the total number of files being scanned not the sizes
Scanning speed depends on the total updated number of Files
disabling the "Show Icons" button increases the Scanning speed
as an example scanning about 1000 File on the same machine may take about 10 seconds
as an example scanning about 1000 File on two machines over network with a speed of 10 MBPS may take about 15 seconds
Synchronization speed depends on the total number of files being scanned and their sizes, it also depends on network speed