Also called the system bus, the frontside bus is the data path connecting the CPU and main memory (RAM). The CPU and memory constantly exchange information across the FSB in order to complete tasks. The FSB is the most important bus in your computer.

The primary bus interface that connects a microprocessor to other system devices via the Northbridge system chipset. Typically, it allows the processor to communicate with main memory (RAM), the system chipset, PCI devices, the AGP card, and other peripheral buses. It also connects to the Level 2 cache unless the processor has a backside bus.