Socket 370 (also known as the PGA370 socket) is a common format of CPU socket first used by Intel for Pentium III and Celeron processors to replace the older Slot 1 CPU interface on personal computers. The "370" refers to the number of holes in the socket for CPU pins. Modern Socket 370 fittings are usually found on Mini-ITX motherboards and embedded systems.
Socket 370 was originally used for the Intel Celeron, but later became the socket/platform for the Coppermine and Tualatin Pentium III processors, as well as the Via-Cyrix Cyrix III, later renamed the VIA C3. Some motherboards that used Socket 370 support Intel processors in dual CPU configurations. Others allowed the use of a Socket 370 or Slot 1 CPU, although not at the same time.
Although not electrically compatible, the socket has also been used in several non-x86 computers. Sun Microsystems used Socket 370 for several models of their UltraSPARC CPU, while Umax repackaged the PowerPC 603e in Socket 370 for some of their Macintosh clones.
The weight of a Socket 370 CPU cooler should not exceed 180 grams. Heavier coolers may result in damage to the die when the system is not properly handled.
This platform is not wholly obsolete, but its use is today limited to the above specialty applications, having been superseded by Socket 423/478/775 (for Pentium 4 and Core 2 processors). Via is at present still producing Socket 370 processors but committed to migrating their processor line to ball grid array packages.