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.
you don't need to upgrade heatsinks installed on motherboards unless you are doing some extreme overclocks on your system,, on a G41,, probably not...
at most if you are worried about how hot it is getting, buy a scythe 40mm fan and aim it to blow over the heatsink
the main function of the chipset is to drive the functions on the MB, such as PCI lanes, USB and storage --- other things such as video and ethernet are controlled by seperate chips on the board and don't typically need a heatsink