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LGA 1151
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LGA 1151
Release dateSeptember 1, 2015 (2015-09-01)
Designed byIntel
Manufactured byLotes
TypeLGA-ZIF
Chip form factorsFlip-chip
Contacts1151
FSB protocolPCI Express
Processor dimensions37.5 × 37.5 mm
1,406.25 mm²[1]
Processors
PredecessorLGA 1150
SuccessorLGA 1200
Memory support
This article is part of the CPU socket series

LGA 1151,[2] also known as Socket H4, is a type of zero insertion force flip-chip land grid array (LGA) socket for Intel desktop processors which comes in two distinct versions: the first revision which supports both Intel's Skylake[3] and Kaby Lake CPUs, and the second revision which supports Coffee Lake CPUs exclusively.

LGA 1151 is designed as a replacement for the LGA 1150 (known as Socket H3). LGA 1151 has 1151 protruding pins to make contact with the pads on the processor. The Fully Integrated Voltage Regulator, i.e. a voltage regulator which integrated on the CPU's die, introduced with Haswell and Broadwell, has again been moved to the motherboard.

Most motherboards for the first revision of the socket support solely DDR4 memory,[2] a lesser number support DDR3(L) memory,[4] and the least number have slots for both DDR4 or DDR3(L) but only one memory type can be installed.[5] Some have UniDIMM support, enabling either type of memory to be placed in the same DIMM, rather than having separate DDR3 and DDR4 DIMMs.[6] The second revision socket motherboards support only DDR4 memory.

Skylake, Kaby Lake, and Coffee Lake chipsets support VT-d, Intel Rapid Storage Technology, Intel Clear Video Technology, and Intel Wireless Display Technology (an appropriate CPU is required). Most motherboards with the LGA 1151 socket support varying video outputs (DVI, HDMI 1.4 or DisplayPort 1.2 – depending on the model). VGA output is optional since Intel dropped support for this video interface starting with Skylake.[7] HDMI 2.0 (4K@60 Hz) is only supported on motherboards equipped with Intel's Alpine Ridge Thunderbolt controller.[8]

Skylake, Kaby Lake, and Coffee Lake chipsets do not support the legacy conventional PCI interface; however, motherboard vendors may implement it using external chips.

Heatsink

[edit]

The 4 holes for fastening the heatsink to the motherboard are placed in a square with a lateral length of 75 mm for Intel's sockets LGA 1156, LGA 1155, LGA 1150, LGA 1151 and LGA 1200. Cooling solutions should therefore be interchangeable.

LGA 1151 revision 1

[edit]

DDR3 memory support

[edit]

Intel officially states[9][10] that Skylake's and Kaby Lake's integrated memory controllers (IMC) support DDR3L memory modules only rated at 1.35 V and DDR4 at 1.2 V, which led to the speculation that higher voltages of DDR3 modules could damage or destroy the IMC and processor.[11] Meanwhile, ASRock, Gigabyte, and Asus guarantee that their Skylake and Kaby Lake DDR3 motherboards support DDR3 modules rated at 1.5 and 1.65V.[12][13][14]

Skylake chipsets (100 series and C230 series)

[edit]
See also: Sunrise Point
H110 B150 Q150 H170 C236 Q170 Z170
Overclocking CPU (via BCLK[15] only;[16] might be disabled in new motherboards and BIOS releases[17]) + GPU + RAM (limited) CPU (multiplier + BCLK[15]) + GPU + RAM
Kaby Lake CPUs support Yes, after a BIOS update[18]
Coffee Lake CPUs support No
Memory support DDR4 (max. 32 GB total; 16 GB per slot) or

DDR3(L) (max. 16 GB total; 8 GB per slot)[19][20]

DDR4 (max. 64 GB total; 16 GB per slot) or

DDR3(L) (max. 32 GB total; 8 GB per slot)[19][21]

Maximum DIMM slots 2 4
Maximum USB ports 2.0 6 4
3.0 4 6 8 10
Maximum SATA 3.0 ports 4 6 8 6
Processor PCI Express v3.0 configuration 1 ×16 Either 1 ×16; 2 ×8; or 1 ×8 and 2 ×4
PCH PCI Express configuration 6 × 2.0 8 × 3.0 10 × 3.0 16 × 3.0 20 × 3.0
Independent Display Support
(digital ports/pipes) 		3/2 3/3
SATA RAID 0/1/5/10 support No Yes Intel Rapid Storage Technology Enterprise Yes
Intel Active Management, Trusted Execution and vPro Technology No Yes No Yes No
Chipset TDP 6 W
Chipset lithography 22 nm
Release date September 1, 2015[22][23] Q3'15[24] September 1, 2015[22][23] Q4'15[25] September 1, 2015[22][23] August 5, 2015[26]

Kaby Lake chipsets (200 series)

[edit]
See also: Union Point (chipset)

There is no equivalent Kaby Lake chipset analogous to the H110 chipset. Four additional PCH PCI-E lanes in Kaby Lake chipsets are reserved for implementing an M.2 slot to support Intel Optane Memory. Otherwise, corresponding Kaby Lake and Skylake chipsets are practically the same.[27]

Light blue indicates a difference between comparable Skylake and Kaby Lake chipsets.

B250 Q250 H270 Q270 Z270
Overclocking No[28] CPU (multiplier + BCLK[29]) + GPU + RAM
Skylake CPUs support Yes
Coffee Lake CPUs support No
Memory support DDR4 (max. 64 GB total; 16 GB per slot) or

DDR3(L) (max. 32 GB total; 8 GB per slot)[30]

Maximum DIMM slots 4
Maximum USB ports 2.0 6 4
3.0 6 8 10
Maximum SATA 3.0 ports 6
Processor PCI Express v3.0 configuration 1 ×16 Either 1 ×16; 2 ×8; or 1 ×8 and 2 ×4
PCH PCI Express configuration 12 × 3.0 14 × 3.0 20 × 3.0 24 × 3.0
Independent Display Support
(digital ports/pipes) 		3/3
SATA RAID 0/1/5/10 support No Yes
Intel Active Management, Trusted Execution and vPro Technology No Yes No
Intel Optane Memory Support Yes, requires Core i3/i5/i7 CPU[31]
Chipset TDP 6 W[32]
Chipset lithography 22 nm[32]
Release date January 3, 2017[33]

LGA 1151 revision 2

[edit]

The LGA 1151 socket was revised for the Coffee Lake generation CPUs and comes along with the Intel 300-series chipsets.[34] While physical dimensions remain unchanged, the updated socket reassigns some reserved pins, adding power and ground lines to support the requirements of 6-core and 8-core CPUs. The new socket also relocates the processor detection pin, breaking compatibility with earlier processors and motherboards. As a result, desktop Coffee Lake CPUs are officially not compatible with the 100 (original Skylake) and 200 (Kaby Lake) series chipsets.[35] Similarly, 300 series chipsets officially only support Coffee Lake and are not compatible with Skylake and Kaby Lake CPUs.

Socket 1151 rev 2 is sometimes also referred to as "1151-2".

Coffee Lake chipsets (300 series and C240 series)

[edit]

Like with Kaby Lake chipsets, four additional PCH PCI-E lanes in Coffee Lake chipsets are reserved for implementing an M.2 slot to support Intel Optane Memory.

There's a 22 nm version of H310 chipset, H310C, which is sold only in China.[36] Motherboards based on this chipset support DDR3 memory as well.

H310 B365 B360 H370 C246 Q370 Z370 Z390
Overclocking No CPU (multiplier + BCLK[37]) + GPU + RAM
Skylake/Kaby Lake CPUs support No
Coffee Lake (8th gen) CPUs support Yes
Coffee Lake Refresh (9th gen) CPUs support Yes with BIOS update Yes Yes with BIOS update Yes
Memory [DDR4]

by Coffee Lake

generation

8th gen Max. 32 GB total; 16 GB per slot Max. 64 GB total; 16 GB per slot
9th gen Max. 64 GB total; 32 GB per slot Max. 128 GB total; 32 GB per slot[38]
Maximum DIMM slots 2 4
Maximum USB 2.0 ports 10 14 12 14
Maximum

USB 3.1 ports configuration

Gen1 4 Ports 8 Ports 6 Ports 8 Ports 10 Ports
Gen2 N/A Up to 4 Ports Up to 6 Ports N/A Up to 6 Ports
Maximum SATA 3.0 ports 4 6 8 6
Processor PCI Express v3.0 configuration 1 ×16 Either 1 ×16; 2 ×8; or 1 ×8 and 2 ×4
PCH PCI Express configuration 6 × 2.0 20 × 3.0 12 × 3.0 20 × 3.0 24 × 3.0
Independent Display Support (digital ports/pipes) 3/2 3/3
Integrated Wireless (802.11ac) Yes** No Yes** No Yes**
SATA RAID 0/1/5/10 support No Yes No Yes Intel Rapid Storage Technology Enterprise Yes
Intel Optane Memory Support No Yes, requires Core i3/i5/i7/i9 CPU Yes, requires Core i3/i5/i7/i9 or Xeon E CPU Yes, requires Core i3/i5/i7/i9 CPU
Intel Smart Sound Technology No Yes
Chipset TDP 6 W[39][40][41][42][43][44][45][46]
Chipset lithography 14 nm[39] 22 nm[40] 14 nm[41][42][43][44] 22 nm[45] 14 nm[46]
Release date April 2, 2018[47] Q4'18 April 2, 2018 October 5, 2017[48] October 8, 2018[49]

** depends on OEM's implementation


See also

[edit]

References

[edit]

Grokipedia

LGA 1151

View on Grokipedia
from Grokipedia
LGA 1151, also known as Socket H4 or FCLGA1151, is a land grid array (LGA) CPU socket developed by Intel for desktop processors, featuring 1,151 pins that connect the processor's contact pads to the motherboard.[1] It serves as the interface for Intel's sixth-generation Skylake, seventh-generation Kaby Lake, eighth-generation Coffee Lake, and ninth-generation Coffee Lake Refresh processors, including Core i3, i5, i7, and i9 series, as well as select Pentium, Celeron, and Xeon E models.[2] The socket exists in two distinct revisions to ensure compatibility with evolving processor designs and prevent cross-usage: revision 1 (v1), introduced in 2015, supports 6th and 7th generation CPUs with 100- and 200-series chipsets (such as H110, B150, H170, Z170, H270, B250, Z270), while revision 2 (v2), launched in 2017, accommodates 8th and 9th generation CPUs with 300-series chipsets (such as B360, H370, Q370, Z370, Z390).[2] These revisions differ in pin assignments—v2 reallocates pins previously used for integrated graphics power delivery to support higher core counts in Coffee Lake processors—resulting in electrical and mechanical incompatibilities that require matching motherboard revisions.[3] Introduced as a successor to the LGA 1150 socket, LGA 1151 enabled advancements in performance, including support for DDR4 memory, up to 16 PCIe 3.0 lanes from the CPU, and integrated graphics on most models, while maintaining a 37.5 mm × 37.5 mm processor package size and TDP ratings typically from 35W to 95W.[4] In 2020, Intel transitioned to the LGA 1200 socket for 10th-generation Comet Lake processors, marking the end of LGA 1151's production lifecycle, though it remains popular in budget and upgrade builds due to its broad compatibility and affordability.[2]

Introduction

Background and Development

LGA 1151 was introduced by Intel in August 2015 as the successor to the LGA 1150 socket, debuting alongside the sixth-generation Core processors based on the Skylake microarchitecture.[5] This new socket design facilitated the transition from the previous generation's architecture, enabling support for DDR4 memory while maintaining compatibility with low-voltage DDR3L in early implementations.[6] The development of LGA 1151 aligned with Intel's Tick-Tock model, where Skylake represented the "Tock" phase—a major architectural redesign on the established 14 nm process node—following the "Tick" of Broadwell, which had introduced a die shrink but faced production delays.[7] The socket's primary purposes included enhancing power efficiency through refined microarchitectural improvements and preparing the platform for future scalability in core counts, addressing the limitations of prior sockets that capped mainstream desktop processors at four cores. Revision 1 of LGA 1151, launched in 2015, supported Skylake and subsequent Kaby Lake processors, focusing on balanced performance for consumer and business applications.[2] In 2017, Intel released Revision 2 of the LGA 1151 socket to accommodate the Coffee Lake microarchitecture, which increased core counts to six in mainstream models and required updated 300-series chipsets for compatibility.[8] This revision extended the socket's lifecycle while resolving earlier constraints on multi-core performance.[9] Support for LGA 1151 began to phase out following the release of the ninth-generation Coffee Lake Refresh processors in 2018, marking the final major update, culminating in its full replacement by the LGA 1200 socket in 2020 alongside the tenth-generation Comet Lake processors.[2][10]

General Characteristics

The LGA 1151, also known as Socket H4 or FCLGA1151, is a land grid array (LGA) CPU socket featuring 1151 pins arranged in a 40×40 grid configuration, with certain positions reserved or depopulated to accommodate electrical and mechanical requirements.[3] This design facilitates direct electrical contact between the processor package and the motherboard, enabling efficient signal transmission for high-performance computing tasks. The socket employs a zero insertion force (ZIF) lever mechanism, which allows processors to be installed and removed without applying pressure to the pins, thereby minimizing the risk of damage during handling.[11] The contact area of the LGA 1151 measures 37.5 mm × 37.5 mm, providing a compact footprint suitable for standard ATX and micro-ATX motherboard layouts.[12] Electrically, it supports a core voltage (VCC) range of 0.55 V to 1.52 V, allowing for dynamic voltage scaling to balance performance and power efficiency across varying workloads. Power delivery is rated for thermal design power (TDP) up to 95 W for standard processors, with unlocked variants capable of reaching 125 W under overclocked conditions, necessitating appropriate cooling solutions to maintain thermal limits.[13] In terms of signaling interfaces, the LGA 1151 supports a dual-channel DDR4 memory interface, enabling data rates starting at 2133 MT/s and scalable to higher speeds depending on the processor generation.[14] It also provides up to 16 lanes of PCIe 3.0 directly from the CPU, supporting configurations such as x16 for graphics cards or bifurcated x8/x8 setups for multi-GPU or storage applications.[14] The socket is designed primarily for desktop Intel Core, Pentium, Celeron, and Xeon E3 v5/v6 and E-2100 series processors, ensuring compatibility with mainstream computing platforms.[1] While the two revisions of the LGA 1151 share these core traits, they differ in specific pin assignments to support evolving processor architectures.

Physical Specifications

Socket Design

The LGA 1151 socket employs a land grid array (LGA) configuration with 1,151 surface-mount pins that interface with the matching land pads on the FCLGA1151 processor package, enabling a zero-insertion-force connection for reliable electrical and mechanical coupling. The socket is implemented using ball grid array (BGA) packaging on the motherboard, allowing for direct soldering and high-density integration without through-hole mounting. This design facilitates efficient heat dissipation and compact board layouts by distributing the pins across the socket base.[15] The pin layout features a central 37.5 × 37.5 mm active area housing the primary signal pins for data transfer, address lines, and control signals, while power (Vcc) and ground (Vss) pins are strategically distributed in outer planes to minimize inductance and ensure stable voltage delivery under load. With a uniform pin pitch of 0.914 mm, the arrangement supports high-speed signaling while adhering to manufacturing tolerances for precise alignment. The overall processor contact area measures 37.5 mm × 37.5 mm, optimizing compatibility with standard desktop motherboards.[13] Installation involves aligning the processor using its corner notches and the gold triangle indicator (marking pin 1 location) with corresponding guides on the socket to prevent misalignment or damage. The CPU is then lowered onto the pins, and the integrated load mechanism—a lever-based retention arm—is engaged to apply uniform downward pressure, securing the package without requiring manual force on the contacts. This process ensures intimate pin-to-land contact for optimal performance. The socket is rated for at least 20 insertion and removal cycles, providing durability for typical upgrade scenarios.[16][17] Compared to its predecessor, the LGA 1150 socket, the LGA 1151 maintains the same 0.914 mm pin pitch but refines the mechanical keying and contact distribution for enhanced signal integrity in higher-frequency operations. The socket includes four peripheral mounting holes compatible with standard heatsink retention brackets for secure thermal solution attachment.[16]

Heatsink Interface

The heatsink interface for the LGA 1151 socket employs a standard mounting mechanism featuring four threaded standoffs arranged in a square pattern with 75 mm × 75 mm hole spacing, allowing secure attachment to the motherboard.[18] This design facilitates even distribution of force across the socket area during installation.[19] To achieve optimal thermal contact, the interface requires applying 30–50 lbf (pounds force) of mounting force through a backplate and retention bracket, ensuring the heatsink base presses uniformly against the CPU without exceeding structural limits.[20] The thermal interface itself relies on direct contact between the heatsink base and the processor's integrated heat spreader (IHS), typically facilitated by a thin layer of thermal compound to minimize air gaps and enhance heat transfer efficiency.[11] This setup maintains compatibility with Intel's reference coolers, such as the Laminar RM1 series, as well as a wide array of third-party air and liquid cooling solutions designed for LGA 115x sockets, provided they adhere to the mounting dimensions and pressure guidelines.[21] The Independent Loading Mechanism (ILM) mirrors that of the preceding LGA 1150 socket, promoting straightforward upgrades while being refined to handle elevated thermal design power (TDP) demands of supported processors.[22] A noted challenge in implementation is the risk of CPU IHS warping or socket pin damage from uneven or excessive mounting pressure, particularly during overtightening; aftermarket coolers often incorporate reinforced backplates to mitigate this by promoting balanced load distribution and preventing motherboard flex.[20]

Revision 1

Supported Processors

The LGA 1151 Revision 1 socket supports Intel's 6th and 7th generation Core desktop processors, codenamed Skylake and Kaby Lake, respectively. These processors are fabricated on Intel's 14 nm process and integrate Intel HD Graphics 530 (Skylake) or 630 (Kaby Lake) in non-F variants, with "K" models featuring unlocked multipliers for overclocking. Intel released numerous desktop SKUs across both generations, spanning Core i3, i5, i7 families, as well as Pentium and Celeron options.[23][24] The 6th generation Skylake processors launched on August 5, 2015, introducing DDR4 memory support to mainstream desktops. They feature up to 4 cores and 8 threads, with thermal design powers (TDP) of 35 W to 91 W. Key features include support for DDR4-2133 memory and up to 16 PCIe 3.0 lanes from the CPU. Representative desktop models are summarized below:
ModelCores/ThreadsBase/Turbo FrequencyTDPIntegrated GraphicsLaunch Date
Core i7-6700K4/84.0 GHz / 4.2 GHz91 WHD 530Q3'15
Core i5-6600K4/43.5 GHz / 3.9 GHz91 WHD 530Q3'15
Core i5-65004/43.2 GHz / 3.6 GHz65 WHD 530Q3'15
Core i3-61002/43.7 GHz / 3.7 GHz51 WHD 530Q3'15
These models focused on improved efficiency and integrated graphics performance over previous generations. The 7th generation Kaby Lake processors, released on January 5, 2017, refined the Skylake architecture with higher clocks and DDR4-2400 support, while maintaining the 4-core maximum for mainstream models. They use the same 14 nm process with HD Graphics 630 and TDP ratings of 35 W to 91 W, enabling boosts up to 4.5 GHz. Notable desktop examples include:
ModelCores/ThreadsBase/Turbo FrequencyTDPIntegrated GraphicsLaunch Date
Core i7-7700K4/84.2 GHz / 4.5 GHz91 WHD 630Q1'17
Core i5-7600K4/43.8 GHz / 4.2 GHz91 WHD 630Q1'17
Core i5-75004/43.4 GHz / 3.8 GHz65 WHD 630Q1'17
Core i3-71002/43.9 GHz / 3.9 GHz51 WHD 630Q1'17
This generation emphasized video playback enhancements and minor IPC gains for general computing and light content creation.

Chipset Support

The Intel 100 Series chipsets were designed for the first revision of the LGA 1151 socket, supporting Skylake processors, while the 200 Series chipsets, launched in 2017, added support for Kaby Lake on updated BIOS. These include enthusiast Z170/Z270, mid-range H170/H270, value B150/B250, entry-level H110, business Q170/Q270, and others like Q150. They provide connectivity via the DMI 3.0 x4 interface (8 GT/s).[25][26]
ChipsetTarget MarketKey Differentiators
Z170/Z270EnthusiastCPU overclocking support; up to 10 USB 3.0 ports; 20 PCIe 2.0 lanes from chipset; memory OC up to DDR4-2133/2400.[25]
H170/H270Mid-rangeNo CPU overclocking; up to 8 USB 3.0 ports; 16 PCIe 2.0 lanes; vPro on select models.
B150/B250ValueNo overclocking; up to 6 USB 3.0 ports; 12 PCIe 2.0 lanes; basic expansion.[27]
H110BasicEntry-level, no overclocking; 4 USB 3.0 ports; 6 PCIe 2.0 lanes; minimal features.
Q170/Q270BusinessvPro and stability; up to 8 USB 3.0 ports; 16 PCIe 2.0 lanes; no overclocking.
Common features include up to 6-8 SATA III ports, NVMe support via M.2, and Intel Rapid Storage Technology for RAID 0/1/5/10. The chipsets provide 16 PCIe 3.0 lanes from the CPU and 6-20 PCIe 2.0 lanes from the chipset. Overclocking is limited to Z-series, with memory support up to 64 GB DDR4-2133 (100 series) or 2400 (200 series).[25] The 100/200 Series are backward compatible within revisions via BIOS updates but incompatible with 300 Series due to pin changes.[28] As of February 2026, the Intel Z370 chipset (LGA 1151 socket) remains compatible only with 8th Generation (Coffee Lake) and 9th Generation (Coffee Lake Refresh) Intel Core processors, along with select Pentium Gold and Celeron models. This includes Core i3/i5/i7/i9 series (e.g., i9-9900K, i7-9700K, i5-9600K, i3-9100). 9th Gen CPUs typically require a BIOS update on Z370 motherboards. No newer Intel CPU generations (10th Gen and later) are supported, as they use different sockets (e.g., LGA 1200, LGA 1700, LGA 1851).[29][30]

Memory and I/O Features

The Revision 1 of the LGA 1151 socket, supporting 6th and 7th generation Intel Core processors, features a dual-channel integrated memory controller handling DDR4 at up to 2133 MHz (Skylake) or 2400 MHz (Kaby Lake), with a maximum capacity of 64 GB. Early boards supported DDR3L-1600, but DDR4 is standard; ECC is available on Xeon E3 v5/v6 models.[23] I/O is managed by 100/200-series chipsets via DMI 3.0 x4 at 8 GT/s. USB support reaches up to 10 ports (USB 3.0 Gen1 at 5 Gbps), plus 14 USB 2.0. Storage includes 6 SATA III ports with RAID options via Intel RST. Integrated graphics (HD 530/630) support up to 3 displays and Quick Sync Video for media acceleration. PCIe provides 16 lanes (3.0) from CPU for GPUs/SSD, plus 6-20 lanes (2.0) from chipset. Premium boards may add USB 3.1 or 10 GbE via controllers. These features suit efficient multitasking but offer less bandwidth than Revision 2 for higher-core workloads.[25]

Revision 2

Supported Processors

The LGA 1151 Revision 2 socket supports Intel's 8th and 9th generation Core desktop processors, codenamed Coffee Lake and Coffee Lake Refresh, respectively, which introduced higher core counts compared to prior generations while maintaining compatibility with 300-series chipsets. These processors are fabricated on Intel's 14 nm process and integrate Intel UHD Graphics 630 in non-F variants, with "K" and "KF" models featuring unlocked multipliers for overclocking. Across both generations, Intel released over 60 desktop SKUs, spanning Core i3, i5, i7, and i9 families, as well as Pentium Gold and Celeron options.[31] The 8th generation Coffee Lake processors launched on October 5, 2017, marking the first mainstream desktop Intel CPUs with 6 cores in i5 and i7 models. They support up to 6 cores and 12 threads, with thermal design powers (TDP) of 65 W for standard models and 95 W for unlocked variants. Key features include support for DDR4-2666 memory and up to 16 PCIe 3.0 lanes from the CPU. Representative desktop models are summarized below:
ModelCores/ThreadsBase/Turbo FrequencyTDPIntegrated GraphicsLaunch Date
Core i3-8350K4/44.0 GHz / 4.0 GHz91 WUHD 630Q4'17
Core i5-84006/62.8 GHz / 4.0 GHz65 WUHD 630Q4'17
Core i5-8600K6/63.6 GHz / 4.3 GHz95 WUHD 630Q4'17
Core i7-87006/123.2 GHz / 4.6 GHz65 WUHD 630Q4'17
Core i7-8700K6/123.7 GHz / 4.7 GHz95 WUHD 630Q4'17
These models exemplify the lineup's focus on multi-threaded performance gains, with non-K variants optimized for efficiency in general computing tasks. The 9th generation Coffee Lake Refresh processors, released on October 8, 2018, extended the architecture to 8 cores and 16 threads in high-end models, introducing the Core i9 branding to mainstream desktops. Like their predecessors, they use a 14 nm process with UHD Graphics 630 (absent in F-series for discrete GPU users) and support DDR4-2666 with up to 16 PCIe 3.0 lanes from the CPU.[32] TDP ratings remain at 65 W for locked models and 95 W for unlocked ones, enabling boosts up to 5.0 GHz. Notable desktop examples include:
ModelCores/ThreadsBase/Turbo FrequencyTDPIntegrated GraphicsLaunch Date
Core i3-91004/43.6 GHz / 4.2 GHz65 WUHD 630Q4'18
Core i5-9600K6/63.7 GHz / 4.6 GHz95 WUHD 630Q4'18
Core i7-9700K8/83.6 GHz / 4.9 GHz95 WUHD 630Q4'18
Core i9-9900K8/163.6 GHz / 5.0 GHz95 WUHD 630Q4'18
Core i9-9900KF8/163.6 GHz / 5.0 GHz95 WNoneQ4'18
This generation emphasized gaming and content creation workloads, with i9 models providing significant multi-core uplift over 8th gen equivalents.

Chipset Support

The Intel 300 Series chipsets were designed specifically for the second revision of the LGA 1151 socket, supporting Coffee Lake and later processors. These chipsets include the enthusiast-oriented Z370 and its refresh Z390, mid-range H370, value B360, entry-level H310, business-focused Q370, and workstation C242. Launched between late 2017 and early 2018, they introduced enhanced connectivity over prior generations while maintaining the LGA 1151 form factor.[30][33]
ChipsetTarget MarketKey Differentiators
Z370EnthusiastSupports CPU overclocking; up to 14 USB 3.1 ports; full 24 PCIe 3.0 lanes from chipset.[30]
Z390Enthusiast (Refresh)Enhanced overclocking with native USB 3.1 Gen 2 support; compatible with 9th-gen processors; 24 PCIe 3.0 lanes.
H370Mid-rangeNo CPU overclocking; up to 14 USB 3.1 ports; 24 PCIe 3.0 lanes; vPro support for business features.
B360ValueNo overclocking; up to 12 USB 3.1 ports; 12 PCIe 3.0 lanes; balanced for mainstream builds.[34]
H310BasicEntry-level with no overclocking; up to 10 USB 3.1 ports; 6 PCIe 3.0 lanes; minimal expansion.
Q370BusinessvPro and stability features; up to 14 USB 3.1 ports; 24 PCIe 3.0 lanes; no overclocking.
C242WorkstationECC memory support; up to 14 USB 3.1 ports; 24 PCIe 3.0 lanes; optimized for professional workloads.
Common features across the 300 Series include support for up to 14 USB 3.1 ports (with configurations varying by model), native NVMe SSD integration via M.2 slots, and Intel Optane memory for caching acceleration. The chipsets connect to the CPU via a DMI 3.0 x4 interface (up to 8 GT/s), providing 16 PCIe 3.0 lanes directly from the processor and 24 PCIe 3.0 lanes from the chipset for expansion cards and storage. Overclocking of the CPU is exclusive to Z-series chipsets (Z370 and Z390), enabling unlocked multipliers on compatible processors alongside memory support up to 64 GB DDR4-2666.[30][35][33] Despite sharing the LGA 1151 socket physically, the 300 Series chipsets are not backward compatible with 100 or 200 Series motherboards due to changes in pin assignments and electrical signaling, requiring new motherboards for Coffee Lake processors.[28]

Memory and I/O Features

The Revision 2 of the LGA 1151 socket, supporting 8th and 9th generation Intel Core processors, features an integrated dual-channel memory controller in the CPU that handles DDR4 memory at up to 2666 MHz, with a maximum capacity of 128 GB on compatible chipsets like Z390.[36] Unlike the first revision, it exclusively supports DDR4 and does not accommodate DDR3L modules.[37] ECC memory is supported on select models, such as Xeon E-series processors, enhancing reliability for server-oriented applications.[36] The platform's I/O capabilities are facilitated by 300-series chipsets, including Z390, which connect to the processor via a DMI 3.0 x4 interface operating at 8 GT/s for efficient data transfer between CPU and peripherals.[38] USB support includes up to 14 ports, with configurations allowing up to 6 USB 3.1 Gen 2 (10 Gbps) and 10 USB 3.1 Gen 1 (5 Gbps) ports, alongside 14 USB 2.0 ports.[37] Storage options encompass 6 SATA III (6 Gbps) ports, with Intel Rapid Storage Technology enabling enhanced RAID configurations such as RAID 0, 1, 5, and 10 for improved performance and data redundancy.[37] Select premium motherboards incorporate 2.5 GbE networking via additional controllers, surpassing the standard 1 GbE provided by the chipset.[39] Integrated graphics in supported processors, such as UHD Graphics 630, allow for up to 3 simultaneous displays and include Intel Quick Sync Video for hardware-accelerated encoding and decoding, optimizing media tasks like video transcoding.[36] Thunderbolt 3 connectivity, offering up to 40 Gbps bidirectional speeds, is available on premium Z390-based boards either natively or via certified add-in cards.[40] These features provide higher overall bandwidth compared to Revision 1, better accommodating the increased core counts in Coffee Lake processors for multitasking and content creation workloads.[38]

Differences and Compatibility

Key Differences Between Revisions

The LGA 1151 socket exists in two primary revisions, often referred to as Revision 1 (supporting 6th and 7th generation Intel Core processors) and Revision 2 (supporting 8th and 9th generation processors), with the key technical variances centered on electrical design to accommodate evolving processor demands.[41][42] A primary difference lies in the pinout configuration, where Revision 2 reassigns reserved pins to additional CPU power rails (VCC) and ground (VSS), with VCC increasing from 128 to 146 pins and VSS from 377 to 391, enabling enhanced power distribution for more demanding workloads.[42][43] This adjustment improves voltage stability and current handling compared to Revision 1. These electrical modifications support higher core counts, as Intel's 6th and 7th generation processors on Revision 1 were designed with up to 4 cores, while Revision 2's upgraded pin assignments and supporting circuitry enabled 6- to 8-core designs in 8th and 9th generation processors.[41][44] In terms of manufacturing, both revisions maintain the same physical form factor with 1151 pins and identical external dimensions, making them visually indistinguishable; however, the underlying PCB traces are rerouted in Revision 2 to align with the altered pin functions, ensuring compatibility only with the intended processor generations.[45][46] BIOS and firmware compatibility represents another critical divergence, as Revision 2 motherboards incorporate updated microcode that rejects Revision 1 processors, preventing boot due to mismatched signaling and power expectations, while the reverse pairing similarly fails without hardware modifications.[43][47] This incompatibility stems from the pinout shifts, which could otherwise risk damage from improper power routing. The performance implications of Revision 2's enhancements include support for higher clock speeds and multi-core scaling, as the improved power delivery reduces voltage droop under load, allowing processors to sustain elevated frequencies across more cores without thermal or electrical throttling.[42][41] To identify the revision of an LGA 1151 socket, users should consult the motherboard manual, which specifies the supported chipsets (e.g., 100/200-series for Revision 1 and 300-series for Revision 2), or employ diagnostic software like CPU-Z to verify the platform details via CPUID instructions.[45][3]

Compatibility Issues

One of the primary compatibility challenges with the LGA 1151 socket arises from the electrical incompatibilities between its two revisions. Processors from the first revision (supporting 6th and 7th generation Intel Core CPUs) cannot boot on second revision motherboards (300-series chipsets for 8th and 9th generation), and vice versa, due to differences in pin configurations that alter power delivery and signaling. Although the physical dimensions and keying notches are identical, allowing the CPU to seat, the mismatched pinout prevents POST and poses risks of short-circuiting components, potentially damaging the CPU or motherboard.[1][43] BIOS updates play a crucial role in intra-revision compatibility but offer no solution for cross-revision issues. For instance, 100-series motherboards require a firmware update to support 7th generation Kaby Lake processors after initially launching for 6th generation Skylake. Similarly, Z370 motherboards typically require a BIOS update to enable 9th generation [Coffee Lake](/page/Coffee Lake) Refresh CPUs, but these updates cannot enable support for the opposing revision's processors due to the underlying hardware differences.[28][1][29] Upgrade paths within the same revision are straightforward, but transitioning between revisions demands a full platform replacement. Users can easily upgrade from Skylake to Kaby Lake on 100- or 200-series motherboards with a BIOS flash, maintaining existing DDR4 memory and I/O configurations. However, moving to Coffee Lake (8th generation) or later requires a new 300-series motherboard, as the socket revisions are not interchangeable.[1] Common errors stem from users overlooking revision distinctions, leading to bent pins during installation attempts or electrical shorts from improper power routing, which can void manufacturer warranties. Such mismatches frequently result in no power-on state or intermittent failures, requiring professional inspection or component replacement to resolve.[48] The LGA 1151 platform reached end-of-life with the release of 9th generation processors in 2018, after which Intel discontinued support for new CPUs on this socket. The successor, LGA 1200, debuted in 2020 for 10th generation Comet Lake processors, marking a shift to increased pin counts and enhanced features without backward compatibility.[2] Reliable workarounds for cross-revision use do not exist, as unofficial modifications like BIOS hacks or pin adapters carry high risks of instability and hardware failure; experts recommend selling existing components and trading up to a newer socket instead.[48]

References

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