Socket Geek

LGA 1366 socket: CPUs, chipsets and cooler fit

LGA 1366, also called Socket B, is the Intel high end socket that arrived in 2008 with the Bloomfield quad core processors. It carries 1,366 contacts for land grid array chips in a 45 by 42.5 mm package. Gulftown six core parts followed in 2010 on 32 nm, and Xeon 55xx and 56xx parts served single and dual socket servers on the same socket.

Quick facts

MakerIntel
Package typeLGA
Contacts1,366
Package sizen/a
Introduced2008
StatusLegacy
MemoryDDR3 triple channel, up to 24 GB on desktop boards
PCIe from the CPUPCIe 2.0 from the X58 chipset (no lanes from the CPU)
Cooler mounting holes80 × 80 mm
ReplacesLGA 775
Replaced byLGA 2011

Overview

The socket connects the CPU over QuickPath Interconnect to an X58 northbridge on desktop boards or a 5500 and 5520 chipset on server boards. Memory runs in three DDR3 channels, which suits editing rigs and home servers with six DIMM slots. There are no integrated graphics on these dies, so a separate card is always required.

LGA 1366 was superseded by LGA 2011 for Sandy Bridge-E in 2011. Because the sockets are physically incompatible, coolers carry over on the shared 80 by 80 mm pattern while boards, chips and memory do not. X58 boards are used or old stock.

Processor generations

CodenameMarketing nameYearsNotes
Bloomfield1st Gen Core i7 quad (45 nm)2008 to 2009Quad core Nehalem desktop parts without graphics, including the i7-920 through i7-975, launched in 2008 with triple DDR3.
Nehalem-EPXeon 55xx (45 nm)2009 to 2010Quad core Nehalem server parts for single and dual socket boards, launched in 2009 with ECC memory.
GulftownSix core desktop and workstation (32 nm)2010 to 2011Six core Westmere parts with 12 MB cache, including the i7-970, 980, 980X and 990X plus the Xeon W3600 series, launched in 2010 with triple DDR3.
Westmere-EPXeon 56xx (32 nm)2010 to 2011Dual socket server parts with up to six cores, including the X5600 high power and L5600 low power series with ECC memory, launched in 2010.
Jasper ForestXeon C5500 and C3500 storage2010Nehalem based single, dual and quad core parts with 2 to 8 MB of cache for storage platforms, including the single core Celeron P1053 at 30 W from February 2010.

Chipsets for LGA 1366

X58 enthusiast

Desktop and workstation chipset for single socket LGA 1366 boards with triple DDR3 and multi GPU slots.

ChipsetSegmentNotes
X58Enthusiast

5500 and 5520 server

Tylersburg server chipsets for single and dual socket LGA 1366 boards with registered memory.

ChipsetSegmentNotes
5500Server
5520Server

Socketed HEDT package

LGA 1366 uses a 1,366-contact load plate socket with a lever and retention bracket. The processor has flat lands instead of pins and drops into the socket before the plate closes. Server boards add threaded backplates for M3 heatsink screws, which differ from desktop push pin mounts.

In practice compatibility depends on the chipset stepping and the BIOS age. Gulftown six core parts boot on X58 with current microcode, while Xeon 56xx parts need server boards with registered memory. A board that lists the exact model is the safe choice.

Memory and I/O

LGA 1366 designs use DDR3 memory in three channels, commonly DDR3-800 to 1333 for up to 24 GB across 6 DIMM slots on desktop X58. Three matched modules give the rated bandwidth, with the remaining slots filled in matched sets of three. Server boards take registered DIMMs instead.

PCI Express is revision 2.0 from the X58 chipset for graphics and fast storage, commonly as two x16 slots for multi GPU builds. The Socket vs chipset: what decides whether a CPU works guide covers Intel pairing rules.

Platform lifecycle

LGA 1366 covers Bloomfield from 2008 and Gulftown plus Xeon 56xx from 2010. Intel moved high end desktop to LGA 2011 for Sandy Bridge-E in 2011 with DDR3 continuity but no socket compatibility. No new LGA 1366 parts followed, so boards and chips are used or old stock.

For a working LGA 1366 system the practical path is maintenance: fresh thermal paste, clean fans, an SSD where the board allows, and a memory population in threes. A platform move means a new socket with DDR4. The How to find your CPU socket type guide explains how to confirm the socket before ordering parts.

CPUs on LGA 1366

77 processor pages in the database, newest first.

ProcessorCores / threadsBase / boostTDPLaunched
Intel Core i7-9806 / 123.33 / 3.6 GHz130 WJun 2011
Intel Core i7-990X6 / 123.46 / 3.73 GHz130 WFeb 2011
Intel Xeon E56034 / 41.6 GHz80 WFeb 2011
Intel Xeon E56064 / 42.13 GHz80 WFeb 2011
Intel Xeon E56074 / 42.26 GHz80 WFeb 2011
Intel Xeon E56496 / 122.53 / 2.93 GHz80 WFeb 2011
Intel Xeon L56396 / 122.13 / 2.67 GHz60 WFeb 2011
Intel Xeon L56456 / 122.4 / 2.93 GHz60 WFeb 2011
Intel Xeon W36906 / 123.46 / 3.73 GHz130 WFeb 2011
Intel Xeon X56474 / 82.93 / 3.2 GHz130 WFeb 2011
Intel Xeon X56724 / 83.2 / 3.6 GHz95 WFeb 2011
Intel Xeon X56756 / 123.06 / 3.46 GHz95 WFeb 2011
Intel Xeon X56874 / 83.6 / 3.86 GHz130 WFeb 2011
Intel Xeon X56906 / 123.46 / 3.73 GHz130 WFeb 2011
Intel Xeon X56982 / 44.4 GHz130 WFeb 2011
Intel Xeon W36706 / 123.2 / 3.47 GHz130 WAug 2010
Intel Core i7-9706 / 123.2 / 3.47 GHz130 WJul 2010
Intel Xeon E55032 / 22.0 GHz80 WMar 2010
Intel Xeon E55074 / 42.27 GHz80 WMar 2010
Intel Xeon W35304 / 82.8 / 3.07 GHz130 WMar 2010
Intel Xeon W36806 / 123.33 / 3.6 GHz130 WMar 2010
Intel Xeon X56774 / 83.47 / 3.73 GHz130 WMar 2010
Intel Core i7-980X6 / 123.33 / 3.6 GHz130 WMar 2010
Intel Xeon E56204 / 82.4 / 2.67 GHz80 WMar 2010
Intel Xeon E56304 / 82.53 / 2.8 GHz80 WMar 2010
Intel Xeon E56404 / 82.67 / 2.93 GHz80 WMar 2010
Intel Xeon E56456 / 122.4 / 2.67 GHz80 WMar 2010
Intel Xeon L56094 / 41.87 GHz40 WMar 2010
Intel Xeon L56184 / 81.87 / 2.27 GHz40 WMar 2010
Intel Xeon L56304 / 82.13 / 2.4 GHz40 WMar 2010
Intel Xeon L56386 / 122.0 / 2.4 GHz60 WMar 2010
Intel Xeon L56406 / 122.27 / 2.8 GHz60 WMar 2010
Intel Xeon X56506 / 122.67 / 3.07 GHz95 WMar 2010
Intel Xeon X56606 / 122.8 / 3.2 GHz95 WMar 2010
Intel Xeon X56674 / 83.07 / 3.47 GHz95 WMar 2010
Intel Xeon X56706 / 122.93 / 3.33 GHz95 WMar 2010
Intel Xeon X56806 / 123.33 / 3.6 GHz130 WMar 2010
Intel Celeron P10531 / 21.33 GHz30 WFeb 2010
Intel Core i7-9304 / 82.8 / 3.07 GHz130 WFeb 2010
Intel Xeon EC35294 / 42.13 GHz65 WFeb 2010
Intel Xeon EC55094 / 42.0 GHz85 WFeb 2010
Intel Xeon EC55394 / 82.27 GHz65 WFeb 2010
Intel Xeon EC55494 / 82.53 / 2.93 GHz85 WFeb 2010
Intel Xeon LC35181 / 11.73 GHz23 WFeb 2010
Intel Xeon LC35282 / 41.73 / 1.87 GHz35 WFeb 2010
Intel Xeon LC55184 / 81.73 / 2.13 GHz48 WFeb 2010
Intel Xeon LC55284 / 82.13 / 2.53 GHz60 WFeb 2010
Intel Xeon W35654 / 83.2 / 3.47 GHz130 WNov 2009
Intel Core i7-9604 / 83.2 / 3.47 GHz130 WOct 2009
Intel Xeon L55304 / 82.4 / 2.67 GHz60 WAug 2009
Intel Xeon W35504 / 83.07 / 3.33 GHz130 WAug 2009
Intel Xeon W35804 / 83.33 / 3.6 GHz130 WAug 2009
Intel Xeon W55904 / 83.33 / 3.6 GHz130 WAug 2009
Intel Core i7-9504 / 83.07 / 3.33 GHz130 WJun 2009
Intel Core i7-9754 / 83.33 / 3.6 GHz130 WJun 2009
Intel Xeon E55022 / 21.87 GHz80 WMar 2009
Intel Xeon E55044 / 42.0 GHz80 WMar 2009
Intel Xeon E55064 / 42.13 GHz80 WMar 2009
Intel Xeon E55204 / 82.27 / 2.53 GHz80 WMar 2009
Intel Xeon E55304 / 82.4 / 2.67 GHz80 WMar 2009
Intel Xeon E55404 / 82.53 / 2.8 GHz80 WMar 2009
Intel Xeon L55064 / 42.13 GHz60 WMar 2009
Intel Xeon L55082 / 42.0 / 2.4 GHz38 WMar 2009
Intel Xeon L55184 / 82.13 / 2.4 GHz60 WMar 2009
Intel Xeon L55204 / 82.27 / 2.53 GHz60 WMar 2009
Intel Xeon W35032 / 22.4 GHz130 WMar 2009
Intel Xeon W35052 / 22.53 GHz130 WMar 2009
Intel Xeon W35204 / 82.67 / 2.93 GHz130 WMar 2009
Intel Xeon W35404 / 82.93 / 3.2 GHz130 WMar 2009
Intel Xeon W35704 / 83.2 / 3.47 GHz130 WMar 2009
Intel Xeon W55804 / 83.2 / 3.47 GHz130 WMar 2009
Intel Xeon X55504 / 82.67 / 3.07 GHz95 WMar 2009
Intel Xeon X55604 / 82.8 / 3.2 GHz95 WMar 2009
Intel Xeon X55704 / 82.93 / 3.33 GHz95 WMar 2009
Intel Core i7-9204 / 82.66 / 2.93 GHz130 WNov 2008
Intel Core i7-9404 / 82.93 / 3.2 GHz130 WNov 2008
Intel Core i7-9654 / 83.2 / 3.47 GHz130 WNov 2008

Frequently asked questions

Which processors fit LGA 1366?

Bloomfield quad parts such as the i7-920, Gulftown six core parts such as the i7-980 and i7-990X, workstation Xeons such as the W3690, and server Xeons such as the X5600 and L5600 series on server boards.

Is LGA 1366 the same as LGA 2011?

No. LGA 1366 carries Nehalem and Westmere with QPI. LGA 2011 carries Sandy Bridge-E and later with a different layout. The sockets are physically incompatible.

What memory does LGA 1366 use?

DDR3 in three channels, 800 to 1333 MT/s depending on the processor, up to 24 GB on desktop X58 boards with 6 DIMM slots. Server boards take registered DIMMs for larger totals.

Can LGA 1366 overclock?

Yes, on X58 boards with a K or X suffix part such as the i7-990X. Server boards do not tune.

Do early X58 boards support six core Gulftown parts?

Yes, with a BIOS update that adds Gulftown microcode. Install the update before fitting the six core chip.

Sources and verification

  1. LGA 1366 (Wikipedia, 1366 contacts, X58 and 5500 series chipsets, DDR3)
  2. LGA1366 socket guide (Intel, 1366-contact socket)
  3. X58 Platinum specs (MSI, Socket 1366, X58, triple DDR3, PCIe Gen2)

Facts last checked against these sources on . Page last edited on .