Socket S1 is the CPU socket type used by AMD for their Turion 64, Athlon 64 Mobile, Phenom II Mobile and later Sempron processors, which debuted with the dual-core Turion 64 X2 CPUs on May 17, 2006.

Socket S1 is a 638 pin, low profile, ZIF, 1.27mm pitch socket.^[1] It replaces the existing Socket 754 in the mobile computing segment (e.g. laptops) as well as the microPGA Socket 563 form factor.

Socket S1 CPUs can include support for dual-channel DDR2 SDRAM, dual-core mobile CPUs, and virtualization technology, and compete with the mobile Intel Core 2 processor series.^[2]

Different generations of processors used various pinouts of the S1 socket; processors were not necessarily electrically-compatible with each socket even if they fit mechanically.

• Socket S1g1 or just S1
  • Platforms: Kite and Kite Refresh
  • CPUs: K8 core, HyperTransport 1.0, DDR2 memory
• Socket S1g2
  • Platforms: Puma and Yukon
  • CPUs: K8 Revision G core, HyperTransport 3.0, DDR2 memory
  • Added:
    • Split-power planes and linked power management support
    • Support for possible low voltage processors
• Socket S1g3
  • Platforms: Tigris
  • CPUs: K10.5 core, HyperTransport 3.0, DDR2 memory
• Socket S1g4
  • Platforms: Danube
  • CPUs: K10.5 core, HyperTransport 3.0, DDR3 memory

• List of AMD microprocessors

• AMD Preps to Switch to Socket S1, Socket M2, Socket F
• https://www.amd.com/system/files/TechDocs/31839.pdf (low profile socket S1 design specs)