Slot A
Chip form factorsPGA
FSB protocolEV6
FSB frequency200 MT/s, 266 MT/s
Voltage range1.3–2.05 V
ProcessorsAMD Athlon (500–1000 MHz)
PredecessorSuper Socket 7
SuccessorSocket A

This article is part of the CPU socket series

Slot A is the physical and electrical specification for a 242-lead single-edge-connector used by early versions of AMD's Athlon processor.[1]

The Slot A connector allows for a higher bus rate than Socket 7 or Super Socket 7. Slot A motherboards use the EV6 bus protocol, a technology originally developed by Digital Equipment Corporation (DEC) for its Alpha 21264 microprocessor.

A Slot A CPU on the left compared to a Slot 1 CPU (connector rotated by 180 degrees)

Slot A is mechanically compatible but electrically incompatible with Intel's Slot 1. As a consequence, Slot A motherboards were designed to have the connector's installed orientation be rotated 180 degrees relative to Slot 1 motherboards to discourage accidental insertion of a Slot 1 processor into a Slot A motherboard, and vice versa. The choice to use the same mechanical connector as the Intel Slot 1 also allowed motherboard manufacturers to keep costs down by stocking the same part for both Slot 1 and Slot A assemblies.

Slot A was superseded by Socket A.


AMD offered official chipsets for the Slot A CPUs. These are included in the table below.

Model Code name Released CPU support FSB/HT (MHz) Southbridge Features / Notes
AMD-750 chipset AMD-751 August 1999[2] Athlon, Duron (Slot A, Socket A), Alpha 21264[citation needed] 100 (FSB) AMD-756, VIA-VT82C686A AGP 2×, SDRAM
Irongate chipset family; early steppings had issues with AGP 2×; drivers often limited support to AGP 1×; later fixed with "super bypass" memory access adjustment.[3]

Third-party chipsets includes a large number of VIA K-series chipsets.

In practice, third-party chipsets were heavily favoured by motherboard manufacturers. Stability problems and compatibility quirks from these chipsets abounded from manufacturers not following chipset designers' guidelines. This caused long-lasting damage to AMD's reputation, despite AMD having nothing to do with the poorly-realised hardware.[citation needed] A similar incident happened with third-party chipsets for Super Socket 7 CPUs.

See also


  1. ^ "CPU Sockets Chart". Retrieved 2009-04-04.
  2. ^ "AMD-750 Chipset Overview" (PDF). AMD. Retrieved August 1, 2001.
  3. ^ Orozco, Silvino (December 29, 1999). "AMD's Super Bypass - AMD Improves their 750 Chipset". Tom's Hardware. Retrieved November 11, 2022.