I have 4 external 1920x1200 displays connected to my Lenovo Thinkpad X220 Tablet PC, via Diamond DisplayLink based USB adapters.
When I power the besat up, not just cold start, but also, most annoyingly, warm start, from Hibernate (Suspend to Disk) or Suspwend (to RAM) power down modes, it engages in excessive flashing.
The screen blanks and redisplays 15 times!!!
Quite annoying.
Continuing http://andyglew.blogspot.com/2011/12/multiple-displays-on-windows-7-good-but.html