The bottom line: today’s servers need more system bandwidth – a lot more bandwidth. Faster processors need to be pumped with instructions and data if they’re to process information efficiently. Increasingly, that information comes from multiple sources within the box and outside of it. And the processed data has to be passed on to ever more users through permanent 24×7 connections.
In short, the old PCI bus has been pushed to its limit. Some applications have gone beyond it, necessitating alternative technologies to supply the bandwidth that PCI can’t provide. Almost all PC graphics cards now require a dedicated bus, AGP. And in almost all high-end systems, chip-to-chip technologies like Intel’s HubLink have ousted PCI from the role.