OK - wondered if it was an XP issue or slow machines, but they look fine.
Are you using the latest DisplayLink software?
Are the primary graphics drivers up to date?
Are the USB 3.0 Host Controller drivers up to date?
Are you using Aero graphics mode, rather than basic mode?
Those are probably the likely candidates. If this doesn't solve it can you post the logs from one of the machines?
http://kb.displaylink.com/269
Thanks
Wim