| Type | PGA-ZIF |
|---|---|
| Chip form factors | Flip-chip pin grid array |
| Contacts | 478 (not to be confused with the older Socket 478 or the similar Socket 479) |
| FSB frequency | 533 MT/s, 667 MT/s, 800 MT/s |
| Processors |
|
| Predecessor | Socket 479 |
| Successor | Socket P |
This article is part of the CPU socket series | |
Socket M (mPGA478MT) is a CPU socket introduced by Intel in 2006. It was used in all Intel Core products, as well as the Core-derived Dual-Core Xeon codenamed Sossaman. It was also used in the first generation of the mobile version of Intel's Core 2 Duo, specifically, the T5x00 and T7x00 Merom lines (referred to as Napa Refresh), though that line switched to Socket P (Santa Rosa) in 2007.

Socket M typically uses the Intel 945PM/945GM chipsets which support up to 667 MHz FSB and the Intel PM965/GM965 which allows 800 MHz FSB support, though the Socket M, PM965/GM965 combination is less common. The "Sossaman" Xeons use the E7520 chipset. Although conflicting information has been published, no 45 nm Penryn processors have been released for Socket M.
Socket M is pin-compatible with the older mobile Socket 479 (mPGA478A) for Pentium III-M processors but is not electrically compatible. Socket M is not pin-compatible with the older desktop Socket 478 (mPGA478B) for Pentium 4 processors or the newer mobile Socket P (mPGA478MN) for later Core processors by location of one pin; it is also incompatible with most versions of the older mobile Socket 479 (mPGA478C), especially those used for Pentium M, which also used an incompatible pin layout.