Is it correct to say that Exchange 2010 rollups are NGened, while the SP's are not?

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http://serverfault.com – I noticed that while applying rollups to Exchange 2010, that a significant amount of time is being spent on the NGen phase (approx 1 hour for me). I'm not clear if either SP1 or SP2 had a similar NGen process applied to it... well at least I don't remember seeing it in the GUI. Is there any reason to believe that only RUs are NGened, while SPs aren't? (HowTos)