Front-side bus (FSB) is between the CPU and northbridge, while the Back-side bus connects the CPU to the cache.
A front-side bus (FSB) was a computer communication interface (bus) often used in Intel-chip-based computers during the 1990s and 2000s. The competing EV6 bus served the same function for AMD CPUs. Both typically carry data between the central processing unit (CPU) and a memory controller hub, known as the northbridge.
Depending on the implementation, some computers may also have a back-side bus that connects the CPU to the cache. This bus and the cache connected to …