What's the difference between the Intel Rapid Storage Technology (RST) and Intel Chipset software (and INF update utility)?
The Intel Chipset software provides drivers for the specific Intel-based hardware on the motherboard in your computer. The motherboard chipset works in concert with the processor and other hardware to make the computer do things. Things like integrated graphics, hard drive controller, integrated network cards, special motherboard features, USB controllers, and the like can't be used to their full potential without the chipset drivers.
The Intel INF Update Utility is a helper program to periodically check to see if your chipset drivers are current or need updating.
The Intel Matrix Storage Manager lets you monitor and control the features of the motherboard's hard drive controller, specifically the monitoring and management of hardware defined RAID (http://en.wikipedia.org/wiki/RAID) arrays.
The Intel RST (Rapid Storage Technology) driver is the operating system driver to let Windows talk to the motherboard's RAID controller.
The Intel RST (Rapid Storage Technology) OROM is the firmware for the motherboard's RAID controller and lets he hardware control the hard drives in various RAID configurations. This is what figures out what to do with the RAID disks and how to do it before the computer loads the operating system.
Hope this clears things up for you.