LGA 2011, also called Socket R, is a CPU socket by Intel. Released on 14 November 2011, it replaces Intel's LGA 1366 (Socket B) and LGA 1567 in the performance and high-end desktop and server platforms. The socket has 2011 protruding pins that touch contact points on the underside of the processor.
The LGA 2011 socket uses QPI to connect the CPU to additional CPUs. DMI 2.0 is used to connect the processor to the PCH. The memory controller and 40 PCI Express (PCIe) lanes are integrated on the CPU. On a secondary processor an extra ×4 PCIe interface replaces the DMI interface. As with its predecessor LGA 1366, there is no provisioning for integrated graphics. This socket supports four DDR3 or DDR4 SDRAM memory channels with up to three unbuffered or registered DIMMs per channel, as well as up to 40 PCI Express 2.0 or 3.0 lanes. LGA 2011 also has to ensure platform scalability beyond eight cores and 20 MB of cache.
The LGA 2011 socket is used by Sandy Bridge-E/EP and Ivy Bridge-E/EP processors with the corresponding X79 (E – enthusiast class) and C600-series (EP – Xeon class) chipsets. LGA 2011-1, an updated generation of the socket and the successor of LGA 1567, is used for Ivy Bridge-EX (Xeon E7 v2) and Haswell-EX (Xeon E7 v3) CPUs, which were released in February 2014 and May 2015, respectively. LGA 2011-v3 (also referred to as LGA 2011-3) is another updated generation of the socket, used for Haswell-E and Haswell-EP CPUs, which were released in August and September 2014, respectively. Updated socket generations are physically similar to LGA 2011, but the used electrical signals and ILM keying prevent them from being backward compatible with older CPUs.
Intel CPU sockets use the so-called Independent Loading Mechanism (ILM) retention device that holds the CPU in place while applying an exact amount of force required for a CPU to be properly seated. As part of their design, ILMs have differently placed protrusions which are intended to mate with cutouts in CPU packagings. These protrusions, also known as ILM keying, have the purpose of preventing installation of incompatible CPUs into otherwise physically compatible sockets, and preventing ILMs to be mounted with a 180-degree rotation relative to the CPU socket.
Different variants (or generations) of the LGA 2011 socket and associated CPUs come with different ILM keying, which makes it possible to install CPUs only into generation-matching sockets. CPUs that are intended to be mounted into LGA 2011-0, LGA 2011-1 or LGA 2011-v3 sockets are all mechanically compatible regarding their dimensions and ball patternpitches, but the designations of contacts are different between generations of the LGA 2011 socket and CPUs, which makes them electrically and logically incompatible. Original LGA 2011 socket is used for Sandy Bridge-E/EP and Ivy Bridge-E/EP processors, while LGA 2011-1 is used for Ivy Bridge-EX (Xeon E7 v2) and Haswell-EX (Xeon E7 V3) CPUs, which were released in February 2014 and May 2015, respectively. LGA 2011-v3 socket is used for Haswell-E and Haswell-EP CPUs, which were released in August and September 2014, respectively.
Two types of ILM exist, with different shapes and heatsink mounting hole patterns: square ILM (80×80 mm mounting pattern), and narrow ILM (56×94 mm mounting pattern). Square ILM is the standard type, while the narrow one is alternatively available for space-constrained applications. A matching heatsink is required for each ILM type.
Information for the Intel X79 (for desktop) and C600 series (for workstations and servers, codenamed Romley) chipsets is in the table below. The Romley (EP) platform was delayed approximately one quarter, allegedly due to a SAS controller bug.
The X79 appears to contain the same silicon as the C600 series, with ECS having enabled the SAS controller for one of their boards, even though SAS is not officially supported by Intel for X79.
Sandy Bridge-E, Ivy Bridge-E and Haswell-E processors are not bundled with standard air-cooled CPU coolers. Intel is offering a standard CPU cooler, and a liquid-cooled CPU cooler, which are both sold separately.
Sandy Bridge-E and Ivy Bridge-E are compatible with the X79 chipset.