[brightball]

I'm going to assume that some of the adjustments they made to improve the scheduler are the cause of this. More checkins with the scheduler on tight loops prevents your entire server from locking up from a runaway infinite loop...but trades some slight overhead.

IMO I'd vote for stability over raw performance numbers every single time since the raw performance numbers depend on "best circumstances" and stability accounts for "worst circumstances". You'll see the latter in reality a lot while the former doesn't exist outside of benchmarks.