If you have the Unlimited Power option on, there is a chance that the game may crash in some levels. This is particularly in those levels where there are a number of friendly NPCs around - the levels around the Templar Base in particular.
The reason is that the Unlimited Power option also applies to friendly NPCs (and may apply to enemies for all I know). The friendly NPCs then trigger their abilities constantly, as the AI is set to use an ability when the power is high enough.
The constant activation of abilities can overload the game and cause it to crash. Disabling the Unlimited Power option gets around this. The problem mainly manifests itself later in the game, by which stage you should have enough power to not really need the option anyway.
[Edited by eboni, 6/4/2008 7:17:31 AM]