Socket 370

Socket 370. Also known as PGA370, it is a common CPU socket first introduced by Intel in 1999 as a low-cost alternative to its Slot 1 interface for Pentium III processors. The socket's design, featuring 370 pins in a Pin Grid Array (PGA) format, marked a return to a more traditional and cost-effective socketed processor package. It became the dominant platform for Intel's budget and mainstream desktop computers throughout the late 1990s and early 2000s, also seeing adoption by other chip manufacturers.

Overview

The development of this socket was driven by Intel's need to reduce manufacturing costs for its value-oriented Celeron line, which initially used the more expensive Slot 1 cartridge. Its introduction coincided with the "Coppermine" revision of the Pentium III, which integrated the L2 cache directly onto the processor die. This architectural shift made the large cartridge of Slot 1 unnecessary, allowing for a compact socket design. The platform's success was cemented by its support from major motherboard manufacturers like ASUS, Gigabyte Technology, and MSI, who produced a wide range of compatible boards. This ecosystem provided consumers with a versatile and affordable foundation for building personal computer systems during a period of rapid technological advancement.

Technical specifications

The interface is a Zero Insertion Force (ZIF) socket with 370 pins arranged in a 37x37 Pin Grid Array. It initially supported a Front-side bus (FSB) speed of 66 MHz for early Celeron processors, later scaling to 100 MHz and 133 MHz for subsequent Pentium III and Tualatin-core CPUs. Core voltages for supported processors ranged from 1.05 volts for later mobile designs to 2.2 volts for earlier models. The socket mechanically differed from the contemporary Socket 423 for early Pentium 4 processors and the later Socket 478. A key physical limitation was its inability to natively support the larger Integrated Heat Spreader (IHS) that became standard on later Intel processors, though some aftermarket coolers were adapted for it.

Processor compatibility

Primary compatibility was with Intel's own x86 microprocessors, starting with the Mendocino-core Celeron and encompassing most Pentium III processors, including the Coppermine and Tualatin cores. The final and most advanced CPUs officially supported were the 1.4 GHz Tualatin-core Pentium III-S processors. Notably, the socket also saw use by other companies; VIA Technologies produced the VIA Cyrix III and VIA C3 processors specifically for this platform. Furthermore, with the use of a slocket adapter, users could install older Slot 1 processors, providing upgrade flexibility. Certain later motherboards with updated voltage regulation modules (VRMs) could even unofficially support the power-efficient Pentium M mobile processors through modified adapters.

Motherboard chipsets

A wide array of Intel chipsets supported the platform, starting with the Intel 440BX, which was carried over from the Slot 1 era via slocket adapters. Native support began with the value-oriented Intel 810 and the more feature-rich Intel 820. The dominant chipsets for performance systems were the Intel 815 and its variants, which offered integrated graphics and official support for 133 MHz FSB and PC133 SDRAM. Competing chipsets from other firms, such as the VIA Apollo Pro133A and the SiS 630, provided strong alternatives, often adding support for newer technologies like AGP 4x and ATA-100 before Intel's own offerings. These chipsets powered systems that competed directly with those based on AMD's Socket A and Athlon processors.

Variants and successors

A key variant was the flipped pinout version used for Tualatin-core processors, which required a compatible motherboard or a physical adapter known as a "PowerLeap" to function on older boards. The socket was also used in mobile form factors for some Pentium III-M processors in laptops. Its official desktop successor was Socket 478, introduced with the Northwood-core Pentium 4, which moved to a new NetBurst microarchitecture and required higher FSB speeds. The platform's legacy lived on in embedded systems, and its design philosophy influenced subsequent low-cost sockets. The competing AMD platform of the era, Socket A, offered a similar lifespan and upgrade path for users of Athlon and Duron processors. Category:CPU sockets Category:Intel microprocessors Category:Computer hardware standards