I assume you mean 125F. No, that's not too hot. If that's the same heatsink I have on my A7N8X Deluxe it was pretty notorious for being slightly concave on the bottom and providing limited cooling. (Remember though, that some boards have no heatsink at all on the NB) If you can get to the back of the board you can remove it and put some better TIM on it or just replace it. However, you only need to do this if you are really going to push the board to the extreme. Mine was fine up to 205fsb without doing anything to the NB cooler.