T60p temperatures going strange

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So it's been several mounts since I've been using my favorite T60p (2007-A16) with C2D T5600 CPU.
This evening I cleaned the heatsink with alcohol, put some grease on the vent, and at the moment I'm taking a look at the temperatures.
When watching a HD video on vimeo for example, temperature rises up to 85* C.
When idling (when browsing FB & stuff) temperature is around 60-65* C.
But the strange thing is this - when idling on Max Performance - 65*, when idling on Max Battery life - 49*. Seems logical but the strangest thing that I've noticed is that switching just from Max Performance to Max bat Life decreased instantly the temperature with 5-6* (from 63* C to 56* C) It's really strange to get such fast reaction in my opinion.
I'm using CPUID Hardware monitor to monitor temperatures.


Share some experience please.