I remember when most Motherboard manufacturers started using fans to cool the chipset...then the fans would fail or slow down...motherboard would lock up or fail...many people calling support.
Fans are no longer favored on Motherboards as most if not all manufacturers now just use heatsinks.
Also a lot of the southbridge/northbridge/MCH components got moved to the CPU itself (like the memory controler, or part of the PCI-e controller), so the need for cooling is less important with these modern controllers. These also run at lower voltages now thanks to die shrinks.