[ The PC Guide | Systems and Components Reference Guide | Motherboard and System Devices | System BIOS | BIOS Settings | Advanced Features ] Fast A20 / A20 Gate Option In order to fully understand this setting you need to understand what the A20 line (21st address line) is and what its significance is. In a nutshell, the A20 line is used to control access to the high memory area, the first 64 KB or so of extended memory. This line is normally controlled by the keyboard controller. To improve performance, newer systems have this control function built into the chipset as well. To have the chipset control the A20 line and improve performance, enable this option. This setting is normally enabled by default. There is rarely any reason to disable this.
|