LGA 1156 socket: CPUs, chipsets and cooler fit
LGA 1156, also called Socket H, is the Intel desktop socket that arrived in September 2009 with the Lynnfield quad core processors. It carries 1,156 contacts for land grid array chips in a 37.5 by 37.5 mm package. Clarkdale dual parts with on-package Ironlake graphics followed in January 2010, which moved the memory controller and graphics onto the processor package for the first time in this line.
Quick facts
| Maker | Intel |
|---|---|
| Package type | LGA |
| Contacts | 1,156 |
| Package size | n/a |
| Introduced | September 2009 |
| Status | Legacy |
| Memory | DDR3-1066 and 1333, two channels, up to 16 GB |
| PCIe from the CPU | PCIe 2.0 x16 from the CPU, plus chipset lanes for the rest |
| Cooler mounting holes | 75 × 75 mm |
| Replaces | LGA 775 |
| Replaced by | LGA 1155 |
Overview
The socket serves two very different dies. Lynnfield quads use a single 45 nm die with no graphics block and need a separate card on any board. Clarkdale duals pair a 32 nm CPU die with a 45 nm graphics and memory controller die, so H55, H57 and Q57 boards show video from board outputs while P55 boards ignore the graphics block. All processors and boards on this socket interoperate at the CPU level, and only the video wiring splits them.
LGA 1156 was superseded by LGA 1155 in 2011 with a new notch position and Sandy Bridge silicon. Because the sockets look alike, boards and chips do not cross between them. Coolers carry over on the shared 75 by 75 mm pattern, while boards, chips and memory rules do not.
Processor generations
| Codename | Marketing name | Years | Notes |
|---|---|---|---|
| Lynnfield | 1st Gen Core quad (45 nm) | 2009 to 2010 | Quad core Nehalem parts without graphics, including the Core i5-750 and Core i7-870 plus Xeon X3400, launched in September 2009 with DDR3-1333. |
| Clarkdale | 1st Gen Core dual with graphics (32 nm) | 2010 to 2011 | Dual core Westmere parts with Ironlake graphics, including the Core i3-500 series, Core i5-600 series, Pentium G6000 series and Celeron G1000 series, launched in January 2010 with DDR3-1066 and 1333. |
Chipsets for LGA 1156
5 series with graphics
Boards with display outputs for Clarkdale integrated graphics, launched in 2010. FDI wiring carries video from the CPU package.
| Chipset | Segment | Notes |
|---|---|---|
| H55 | Mainstream | |
| H57 | High-end | |
| Q57 | Business |
P55 performance
Performance boards without display outputs. Clarkdale and Lynnfield CPUs run at rated clocks while integrated graphics stay unused.
| Chipset | Segment | Notes |
|---|---|---|
| P55 | High-end |
Socketed desktop package
LGA 1156 uses a 1,156-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. This was the first mainstream Intel desktop socket to move the memory controller onto the processor die.
In practice compatibility depends on the chipset and the video wiring. Clarkdale graphics need H55, H57 or Q57 with FDI outputs, while P55 runs any LGA 1156 chip with a separate card. Lynnfield quads have no graphics block at all. A board that lists the exact model is the safe choice.
Memory and I/O
LGA 1156 designs use DDR3 memory in two channels, commonly DDR3-1066 and 1333 for up to 16 GB across 4 DIMM slots. Clarkdale Pentium parts such as the G6960 officially take DDR3-1066, while Core i3 and i5 parts take DDR3-1333. Two matched modules give the rated bandwidth, with the remaining slots filled in matched sets.
PCI Express is revision 2.0 with 16 lanes from the CPU for graphics, either as one x16 slot or two x8 slots on boards that split them, plus chipset lanes for the rest. The Socket vs chipset: what decides whether a CPU works guide covers Intel pairing rules.
Platform lifecycle
LGA 1156 covers Lynnfield from September 2009 and Clarkdale from January 2010. Intel moved mainstream desktop to LGA 1155 for Sandy Bridge in 2011 with DDR3 continuity but no socket compatibility. No new LGA 1156 parts followed, so boards and chips are used or old stock.
For a working LGA 1156 system the practical path is maintenance: fresh thermal paste, clean fans, an SSD where the board allows, and a memory population that matches. A platform move means a new socket with DDR3 or DDR4. The How to find your CPU socket type guide explains how to confirm the socket before ordering parts.
CPUs on LGA 1156
31 processor pages in the database, newest first.
| Processor | Cores / threads | Base / boost | TDP | Launched |
|---|---|---|---|---|
| Intel Pentium G6960 | 2 / 2 | 2.93 GHz | 73 W | Jan 2011 |
| Intel Xeon L3403 | 2 / 2 | 2.0 GHz | 30 W | Oct 2010 |
| Intel Pentium G6951 | 2 / 2 | 2.8 GHz | 73 W | Sep 2010 |
| Intel Core i3-560 | 2 / 4 | 3.33 GHz | 73 W | Aug 2010 |
| Intel Core i5-760 | 4 / 4 | 2.8 / 3.33 GHz | 95 W | Jul 2010 |
| Intel Core i7-870S | 4 / 8 | 2.67 / 3.6 GHz | 82 W | Jul 2010 |
| Intel Core i7-880 | 4 / 8 | 3.07 / 3.73 GHz | 95 W | May 2010 |
| Intel Xeon X3480 | 4 / 8 | 3.07 / 3.73 GHz | 95 W | May 2010 |
| Intel Core i3-550 | 2 / 4 | 3.2 GHz | 73 W | May 2010 |
| Intel Core i5-655K | 2 / 4 | 3.2 / 3.47 GHz | 73 W | May 2010 |
| Intel Core i7-875K | 4 / 8 | 2.93 / 3.6 GHz | 95 W | May 2010 |
| Intel Core i5-680 | 2 / 4 | 3.6 / 3.87 GHz | 73 W | Apr 2010 |
| Intel Xeon L3406 | 2 / 4 | 2.27 / 2.53 GHz | 30 W | Mar 2010 |
| Intel Core i3-530 | 2 / 4 | 2.93 GHz | 73 W | Jan 2010 |
| Intel Core i5-670 | 2 / 4 | 3.47 / 3.73 GHz | 73 W | Jan 2010 |
| Intel Celeron G1101 | 2 / 2 | 2.26 GHz | 73 W | Jan 2010 |
| Intel Core i3-540 | 2 / 4 | 3.07 GHz | 73 W | Jan 2010 |
| Intel Core i5-650 | 2 / 4 | 3.2 / 3.47 GHz | 73 W | Jan 2010 |
| Intel Core i5-660 | 2 / 4 | 3.33 / 3.6 GHz | 73 W | Jan 2010 |
| Intel Core i5-661 | 2 / 4 | 3.33 / 3.6 GHz | 87 W | Jan 2010 |
| Intel Core i5-750S | 4 / 4 | 2.4 / 3.2 GHz | 82 W | Jan 2010 |
| Intel Core i7-860S | 4 / 8 | 2.53 / 3.47 GHz | 82 W | Jan 2010 |
| Intel Pentium G6950 | 2 / 2 | 2.8 GHz | 73 W | Jan 2010 |
| Intel Core i7-870 | 4 / 8 | 2.93 / 3.6 GHz | 95 W | Sep 2009 |
| Intel Core i5-750 | 4 / 4 | 2.67 / 3.2 GHz | 95 W | Sep 2009 |
| Intel Core i7-860 | 4 / 8 | 2.8 / 3.47 GHz | 95 W | Sep 2009 |
| Intel Xeon X3430 | 4 / 4 | 2.4 / 2.8 GHz | 95 W | Sep 2009 |
| Intel Xeon X3440 | 4 / 8 | 2.53 / 2.93 GHz | 95 W | Sep 2009 |
| Intel Xeon X3450 | 4 / 8 | 2.67 / 3.2 GHz | 95 W | Sep 2009 |
| Intel Xeon X3460 | 4 / 8 | 2.8 / 3.47 GHz | 95 W | Sep 2009 |
| Intel Xeon X3470 | 4 / 8 | 2.93 / 3.6 GHz | 95 W | Sep 2009 |
Frequently asked questions
Which processors fit LGA 1156?
Lynnfield quad parts such as the Core i5-750 and Core i7-870 plus Clarkdale dual parts such as the Core i3-540 and Pentium G6960. Xeon X3400 parts for entry servers fit the same socket.
Is LGA 1156 compatible with LGA 1155?
No. They share the maker name pattern but the notch positions and pinouts differ, so processors do not fit the other socket.
What memory does LGA 1156 use?
DDR3 in two channels, 1066 to 1333 MT/s depending on the processor, up to 16 GB on desktop boards with 4 DIMM slots. ECC needs a server board with a Xeon part.
Can LGA 1156 overclock?
Yes, on P55 boards with a K suffix part such as the i7-875K. H55 and H57 allow small base clock moves where the board maker permits it.
Does P55 support integrated graphics?
No. Clarkdale graphics need H55, H57 or Q57 with FDI wiring. P55 ignores the graphics block, so those boards need a separate card.
Sources and verification
- LGA 1156 (Wikipedia, 1156 contacts, Lynnfield and Clarkdale, P55 H55 H57 Q57)
- LGA 1156 guide (Clarkdale and Lynnfield specs, P55 H55 H57 Q57 chipset table)
- GA-P55-UD3L specs (Gigabyte, LGA1156, P55, dual DDR3, PCIe 2.0)
Facts last checked against these sources on . Page last edited on .