Usually fast validating yes.

Predictor doesn't send WU's out to the same CPU type only ;)

If I mess witht he PC and send them back when there finished (I manually click update), then usually 75% of units I send back will validate on the same day or the next I send them back...

If I keep them all for the 3.5 days (my BOINC network connection prefs), pretty much all of them validate as soon as they reach the servers. :D