As CPU manufacturers achieved faster processing speeds, the ISA/EISA buses could no longer effectively keep up with the CPU. These buses transferred data from the expansion slot to memory and then to the CPU. This prevented the buses from tapping into the faster speeds of the CPU itself.

The local bus, addressed this problem. It bypasses memory and connects directly to the CPU. This allows for faster data transfer.

The local bus is designed as an extension of earlier bus designs. However, it does not replace them. Most PCs today have a combination of the two buses: ISA/EISA and a local bus. This provides for ISA/EISA expansion slots, and local bus expansion slots allowing to PC to support older and newer expansion cards.

This bus comes in two flavors: VESA, and PCI.