Based on Intel's Nehalem architecture and with it came the 1366-pin "Socket B", which like it's predecessor, uses the LGA socket configuration. Later followed an updated LGA-1156 socket, which moved the QPI and PCI-express controller off of the Northbridge and on to the CPU. As a result of the lower pin count it's trade off is LGA-1156 systems can only run in Dual-channel memory mode, as apposed to Triple-channel that is unique to the LGA-1366 platform (and subsequent XEON sockets). The Nehalem's mobile variant was released on September 23, 2009 in the form of the various i7-x20QM and i7-x20XM models, followed by the the i7-x40QM and i7-x40XM models on June 21, 2010.