Intel QuickPath Interconnect

The Intel QuickPath Interconnect (QPI) is a point-to-point processor interconnect developed by Intel which replaced the front-side bus (FSB) in Xeon, Itanium, and certain desktop platforms starting in 2008. It increased the scalability and available bandwidth. Prior to the name's announcement, Intel referred to it as Common System Interface (CSI). Earlier incarnations were known as Yet Another Protocol (YAP) and YAP+.

QPI 1.1 is a significantly revamped version introduced with Sandy Bridge-EP (Romley platform).

QPI was replaced by Intel Ultra Path Interconnect (UPI) in Skylake-SP Xeon processors based on LGA 3647 socket.