Well, it's not a HUGE delta or anything, but when your used to a Swiftech, then yea, it'd catch your eye when your running a windows app at full load. I would hover ar about 40-41C idle at 1.4ghz, but running something pretty cpu intensive, I'd see if pop up to between 45-46C. There's absolutely nothing horrible about those temps, but the change with my Swiftech would be around half that.
Running the chip at stock 1ghz, the delta was very small. I've not had any stability issue's, heat related or not since I've popped this in. Seems to work just great to me.