If you're talking about motherboards, the chipset is I guess, the main 'center' of the motherboard. Not in a CPU sense where everything is processed, but more as in where all the information throughout the computer is linked together in a sense.
Most of the time, the heatsink is sufficiently cooled by the default heatsink. What motherboard do you have? (If you are talking about motherboards, which I am assuming)
I have an EVGA X58 SLI LE board, and I felt the X58 chipset was getting a bit too hot, so I 'modded' it, by adding a small fan and the temperatures went down quite significantly.