Socket G2

Socket G2, also known as rPGA988B or FCPGA988, is a CPU socket developed by Intel for mobile processors in laptop computers. Introduced in January 2011, it features a removable pin grid array (rPGA) design with 988 pins arranged in a 37.5 mm × 37.5 mm package, supporting dual- and quad-core configurations with thermal design power (TDP) ranging from 17 W to 55 W.^[1] The socket was primarily designed for Intel's second-generation Core processor family (Sandy Bridge microarchitecture), serving as the successor to Socket G1, and later extended to third-generation Core processors (Ivy Bridge microarchitecture) launched in 2012.^[1] It accommodates a range of mobile CPUs including Core i3, i5, i7, Pentium, and Celeron models, such as the quad-core Intel Core i7-2960XM (Sandy Bridge) and i7-3840QM (Ivy Bridge), enabling frequencies up to 3.8 GHz with features like Intel Turbo Boost Technology. Compatible with Intel 6-series (e.g., HM65, QM67) and select 7-series chipsets, Socket G2 supports dual-channel DDR3 memory at speeds of 1066–1600 MT/s, Direct Media Interface 2.0, and integrated graphics with up to 16 execution units.^[1]^[2] Notable for its mechanical actuator mechanism—which locks the CPU by rotating clockwise and releases counterclockwise—Socket G2 facilitated upgradability in certain laptop models but became obsolete by June 2013, replaced by Socket G3 (rPGA946B) for Haswell processors.^[1] It played a key role in advancing mobile performance during the early 2010s, emphasizing power efficiency and integrated features like Intel Hyper-Threading and Advanced Vector Extensions (AVX).^[2]

Overview

Introduction

Socket G2, also known as rPGA 988B, is a removable pin grid array (rPGA) CPU socket designed by Intel specifically for mobile processors. Introduced in January 2011, it serves as the interface for second-generation Intel Core i7, i5, i3, Pentium, and Celeron processors based on the Sandy Bridge microarchitecture, manufactured on a 32 nm process.^[1] This socket features 988 pins to enable high-bandwidth connections between the CPU and motherboard.^[1] As a successor to Socket G1 (rPGA 988A), Socket G2 introduced compatibility improvements for enhanced performance in mobile platforms while maintaining incompatibility due to key pin position differences.^[1] It later extended support to third-generation processors under the Ivy Bridge microarchitecture on a 22 nm process, bridging the transition until its replacement by Socket G3 (rPGA 946B) for Haswell-based chips.^[3] Primarily deployed in laptops, it also appeared on select mini-ITX motherboard designs for compact desktop systems.^[4] Socket G2 played a pivotal role in high-performance mobile computing, powering ultrabooks, workstations, and other portable devices with an emphasis on power efficiency and integrated Intel HD Graphics.^[5] Its design facilitated dual-channel DDR3 memory support up to 1600 MHz, contributing to balanced performance in battery-constrained environments.^[1]

Development and release

Socket G2 emerged as the evolution from Socket G1 to accommodate Intel's shift to the 32 nm Sandy Bridge microarchitecture, prioritizing advancements in power efficiency and thermal management to meet the rising needs for high-performance, battery-optimized computing in mobile devices during the early 2010s. This design motivation addressed the growing market for portable systems capable of handling intensive tasks like multimedia processing and multitasking without excessive power draw, building on the integrated graphics and ring bus interconnect introduced in Sandy Bridge. Intel announced plans for Sandy Bridge-based products, including mobile variants compatible with Socket G2, in September 2010, with high-volume shipping slated for early 2011.^[6] The socket officially launched in January 2011 alongside the second-generation Core i3, i5, and i7 mobile processors, marking the debut of rPGA988B as the standard for these chips. Support for the subsequent 22 nm Ivy Bridge architecture was added in April 2012, extending the socket's lifecycle through BIOS updates on compatible 7-series chipsets like QM77. Adoption was swift among major original equipment manufacturers (OEMs), with Socket G2 integrated primarily into laptop motherboards by Dell, HP, and Lenovo for business and consumer ultrabooks and notebooks. Desktop applications remained niche, limited to compact mini-ITX form factors using the mobile-oriented QM77 chipset, such as boards from Jetway and ASRock Industrial, which enabled small-footprint systems for embedded or home theater use.^[7]^[4] The release faced early hurdles due to a manufacturing defect in the 6-series chipsets (including mobile variants like HM65 and QM67), which caused gradual degradation of SATA ports connected to certain controllers, leading Intel to suspend shipments on January 31, 2011, for a silicon fix implemented via a mask change.^[8]^[9] Ivy Bridge support required 7-series chipsets, with no official compatibility on 6-series like HM65.

Technical specifications

Electrical and interface details

Socket G2 utilizes a reduced pin grid array (rPGA) configuration with a 1 mm pitch, enabling compact integration in mobile platforms.^[10] The socket features 988 pins arranged in a 35 × 36 grid array, with an 18 × 15 center section removed to accommodate the processor's integrated heat spreader. The interface protocol relies on the Direct Media Interface (DMI), operating at 5 GT/s for both Sandy Bridge-based processors and Ivy Bridge implementations, replacing the traditional front-side bus (FSB) architecture.^[11]^[2] This point-to-point connection supports up to x4 lanes, providing aggregate bandwidth of 2 GB/s, and facilitates communication between the processor and platform controller hub (PCH).^[2] Voltage specifications include a maximum supply of 5 V and 500 mA per pin, with support for an integrated voltage regulation module (IVR) that enables dynamic power scaling through serial voltage identification (SVID).^[11] Core voltages range from 0.3 V to 1.52 V in active modes, adjusted via multiple rails such as VCC for the core, VCCSA for the system agent, and VDDQ for the memory controller at 1.5 V (DDR3) or 1.35 V (DDR3L).^[2] The memory interface supports DDR3 small outline dual in-line memory modules (SoDIMMs) in a dual-channel configuration, with speeds ranging from 1066 MHz to 1600 MHz and capacities up to 32 GB.^[11]^[2] Power delivery is optimized for mobile environments, with thermal design power (TDP) ratings spanning 17 W for ultra-low voltage variants to 55 W for extreme edition processors, emphasizing adherence to mobile TDP limits for thermal management.^[11]^[2]

Mechanical and physical design

The Socket G2, also known as rPGA988B, features a processor package measuring 37.5 × 37.5 mm, designed primarily for removable Pin Grid Array (rPGA) mounting in mobile platforms, though it serves as the mobile counterpart to Land Grid Array (LGA) formats used in desktops.^[2] This configuration allows for compatibility with PGA-style sockets while enabling easier handling in laptop chassis compared to soldered BGA alternatives. The socket employs a zero insertion force (ZIF) mechanism with a rotating actuator to securely seat the CPU, which locks by turning clockwise and releases by turning counterclockwise, minimizing stress on the pins during installation and ensuring stability within mobile enclosures.^[2] This design facilitates solderless upgrades in compatible laptops, though successful operation requires appropriate BIOS firmware support for the processor variant. Socket G2 was commonly deployed in mobile platforms from 2011 to 2013, aligning with second- and third-generation Intel Core architectures.^[2] Processors for Socket G2 incorporate an integrated heat spreader (IHS) that provides direct contact with the socket and cooling solutions, such as vapor chamber heatsinks prevalent in laptops for efficient thermal dissipation.^[2] The socket's durability is rated for approximately 50 insertion and removal cycles, incorporating anti-static protection to safeguard against electrostatic discharge during handling.^[12]

Compatible hardware

Supported processors

Socket G2 supports mobile processors from Intel's Sandy Bridge and Ivy Bridge microarchitectures, released in 2011 and 2012, respectively. These processors are designed for laptops and mobile workstations, featuring integrated graphics and varying core configurations to balance performance and power efficiency.^[2] The Sandy Bridge series, built on a 32 nm process, includes mobile Core i7 models such as the i7-2960XM (quad-core, 2.7 GHz base frequency, up to 3.7 GHz turbo, 8 MB L3 cache), alongside i5 models like the i5-2540M (dual-core, 2.6 GHz base, up to 3.3 GHz turbo, 3 MB L3 cache), as well as i3, Pentium, and Celeron variants. All incorporate Intel HD Graphics 3000 for basic visual processing. Ivy Bridge processors represent a 22 nm die shrink of Sandy Bridge, enhancing efficiency and graphics capabilities. Key examples include the Core i7-3940XM (quad-core, 3.0 GHz base, up to 3.9 GHz turbo, 8 MB L3 cache) and i5-3380M (dual-core, 2.9 GHz base, up to 3.6 GHz turbo, 3 MB L3 cache), with i3, Pentium, and Celeron options completing the lineup; integrated HD Graphics 4000 provides improved performance over the prior generation. The family encompasses over 22 SKUs, focusing on mobile applications.^[2] Processors span performance tiers from low-power U-series (17 W TDP for ultrathin devices) to high-end QM and XM extreme editions (up to 55 W TDP for demanding workloads), with more than 50 stock-keeping units (SKUs) available across both generations to suit diverse mobile computing needs.^[2] Official support for Socket G2 processors ended around 2015, following the discontinuation of Ivy Bridge models with no subsequent generations compatible with the socket.^[13]^[14]

Motherboard and chipset compatibility

Socket G2 processors, primarily mobile Intel Core series based on Sandy Bridge and Ivy Bridge architectures, are supported by Intel's 6-series and 7-series mobile chipsets. The 6-series chipsets, including HM65, HM67, QM67, QS67, and UM67, were designed for Sandy Bridge processors and provide features such as support for up to two SATA 6 Gb/s ports, USB 2.0/3.0 interfaces, and optional RAID configurations on select models like QM67. The 7-series chipsets, such as HM76, HM77, and QM77, extend compatibility to Ivy Bridge while maintaining backward support for Sandy Bridge, adding native USB 3.0 and enhanced RAID options (0, 1, 5, 10) on vPro-enabled variants like QM77 for enterprise management features including remote BIOS updates and hardware monitoring. Motherboards utilizing Socket G2 are predominantly designed for mobile platforms, featuring compact form factors like those in laptops with soldered or socketed CPU configurations to accommodate thin chassis. While rare in desktop environments, some industrial and mini-ITX boards exist, such as Supermicro's X9SCV-Q series with the QM67 chipset and ASRock Industrial's IMB-170 with QM77, enabling embedded applications with dual-channel DDR3 SODIMM support.^[4] Compatibility with prior-generation hardware is limited; Socket G2 (rPGA988B) differs from Socket G1 (rPGA988A) by the position of a single pin, preventing direct interchange, though some motherboards employ the rPGA989 socket variant that accepts both via mechanical adaptation, often requiring BIOS firmware updates to recognize G1 processors fully. Forward compatibility ends with Haswell processors, which transitioned to Socket G3 (rPGA946B/947B) and are incompatible due to differing pin counts and electrical requirements. These platforms were widely integrated by major OEMs in business and consumer laptops from 2011 to 2014, including Dell's Inspiron and Precision series (e.g., Inspiron 14R 5420), HP's ProBook and EliteBook lines (e.g., EliteBook 8470p), and Lenovo's ThinkPad T-series (e.g., T430), often paired with 6- or 7-series chipsets for balanced performance in ultrabook and workstation designs. Upgrading within the Socket G2 ecosystem, such as installing an Ivy Bridge processor on a Sandy Bridge-era board, typically necessitates a BIOS firmware flash to enable microcode support, as initial 6-series firmware lacks Ivy Bridge recognition, though 7-series boards handle both natively.^[15] Maximum supported RAM varies by processor model, up to 32 GB of DDR3 (1066–1600 MT/s) in dual-channel configuration.^[16]^[17]

Comparisons and variants

Differences from Socket G1

Socket G2 (rPGA988B) maintains the same 988-pin count as its predecessor Socket G1 (rPGA988A), but features a refined pin layout with one pin hole repositioned, rendering the sockets physically incompatible and preventing cross-use of processors.^[1] This adjustment supports enhanced signaling integrity for the integrated graphics processing unit (iGPU), which in Socket G2 platforms is fabricated on the same die as the CPU cores—a shift from Socket G1's Arrandale design, where the iGPU occupied a separate die within the multi-chip module. Both sockets employ Direct Media Interface (DMI) 2.0 at 2.5 GT/s for chipset communication, but Socket G2's architecture enables higher memory bandwidth through support for DDR3-1600 in dual-channel mode, compared to DDR3-1333 maximum on many Socket G1 configurations..html) Architecturally, Socket G2 was optimized for Intel's Sandy Bridge microarchitecture at 32 nm, extending to Ivy Bridge at 22 nm, whereas Socket G1 targeted Nehalem-based Clarksfield (45 nm) and Westmere-based Arrandale (32 nm) processors. This evolution incorporated advanced integrated voltage regulation modules directly on the processor package, reducing external power delivery components and improving transient response for dynamic workloads. In mobile applications, these changes contributed to better power efficiency under load, allowing sustained performance in battery-constrained environments without excessive thermal output. Mechanically, both sockets share a 37.5 mm × 37.5 mm processor footprint and a similar rPGA retention mechanism with a rotating actuator for secure installation in laptop chassis..html) However, Socket G2's optimized pin grid and reinforced socket housing provide better tolerance for thinner, more compact notebook designs, minimizing alignment issues during assembly.^[18] These enhancements enabled Socket G2 processors to achieve higher base and turbo clock speeds—up to 3.7 GHz in quad-core models—while mitigating thermal throttling prevalent in Socket G1 systems under prolonged multi-threaded tasks, thanks to improved Turbo Boost 2.0 implementation and more efficient core scaling.

Transition to Socket G3

Socket G3, also known as rPGA 946B/947, was introduced in June 2013 alongside Intel's Haswell-based mobile processors, marking a shift from the Socket G2 used for Ivy Bridge architectures at the 22 nm process node. This new socket featured 946 pins in a 37.5 mm x 37.5 mm rPGA package, enabling support for PCIe 3.0 interfaces with up to 8 GT/s speeds and integrated voltage regulators that reduced power delivery rails from six to two for improved efficiency.^[19] While Socket G2 supports both DDR3 and DDR3L memory, Socket G3 emphasized DDR3L at 1.35 V with support for DDR3L-RS variants, allowing for denser configurations up to 32 GB while enhancing power savings in mobile systems.^[19] The transition was driven by the need to accommodate Haswell's architectural advancements, including superior power gating, deeper C-states (up to C7 for idle power as low as 2.4 W), and the introduction of Iris Pro graphics with up to 40 execution units for better integrated performance in ultrathin laptops.^[19] Socket G2 reached end-of-life status by mid-2014, as Ivy Bridge production declined and Haswell became the standard for new mobile platforms, superseding the older rPGA 988B design that could no longer support these evolutions without major revisions. Direct compatibility between Socket G2 and G3 was absent, with the sockets having different pin counts (988 for G2 vs. 946 for G3) and differing in pin positioning and electrical signaling, necessitating entirely new motherboards for Haswell processors; while some G2 systems received BIOS updates for late Ivy Bridge models, no such bridges extended to Haswell.^[18] In the market, Socket G2 laptops were phased out from production between 2014 and 2015, while G3 adoption facilitated thinner chassis designs and extended battery life through features like Configurable TDP and enhanced Turbo Boost 2.0.^[19] Legacy G2-based systems received security patches and driver support until approximately 2020, aligning with the end of Windows 7 mainstream maintenance.