LGA 771

LGA 771, also known as Socket J, is a CPU interface introduced by Intel in 2006. It is used in Intel Core microarchitecture and NetBurst microarchitecture based DP-capable server processors, the Dual-Core Xeon is codenamed Dempsey, Woodcrest, and Wolfdale and the Quad-Core processors Clovertown, Harpertown, and Yorkfield-CL. It is also used for the Core 2 Extreme QX9775, and blade servers designated under Conroe-CL.
It was succeeded by LGA 1366 for the Nehalem-based Xeon processors.

Technical specifications

As its name implies, it is a land grid array with 771 contacts. The socket has 771 protruding spring-loaded pins which touch the lands on the underside of the microprocessor.
The "J" in "Socket J" refers to the now-canceled processor codenamed "Jayhawk", which was expected to debut alongside this interface. It is intended as a successor to Socket 604 and takes much of its design from LGA 775 and is almost pin compatible with LGA 775.
Compared to LGA 775 CPUs, LGA 771 CPUs are rotated 90 degrees and have two pins swapped. Small adapters developed by Chinese computer DIY enthusiasts are available to allow LGA 771 CPUs to be installed in LGA 775 motherboards, if the BIOS microcode supports them. This also allows for overclocking of Xeon processors when used in the correct motherboards. Some overclockers have managed quite substantial overclocks such as 4.023GHz on a Xeon X5492 for a total overclock of just over 18%.

Dual core processors

Hyper-threading supported only on 50xx series processors