AMI Mark IV Screamer, Manual

Page: 65 / 93

Advanced CMOS Setup Options,
Continued
Fast Gate A20
Gate A20 controls the ability to access memory addresses
above 1 MB by enabling or disabling access to the processor
address line A20. To remain XT-Compatible and be able to
access conventional memory (from 0 - 1024K), address line
A20 must always be low, so Gate A20 must be disabled.
However, some software programs both enter protected mode
and shut down through the BIOS. For this software, Gate A20
must be constantly enabled and disabled via the keyboard
controller, which can slow processing considerably.
Fast Gate A20 is an alternate method of enabling Gate A20,
which permits access to memory addresses above 1 MB. All
RAM accesses to extended memory addresses above 1 MB
require that Gate A20 be enabled via the keyboard controller,
which is a slow process.
Fast Gate A20 is an alternative method for handling Gate A20
found in many chip sets and some software products. Use Fast
Gate A20 to speed Gate A20 enabling and disabling, which in
turn speeds up programs that constantly change from
addressing conventional memory to addressing memory
addresses above 1 MB. For example, enabling this option
makes programs such as network operating systems execute
faster.
Turbo Switch Function
This option enables the turbo switch.