American Megatrends Super Voyager VLB-III, User Manual, Page: 10 / 138

Chapter 1 System Overview
4
Description,
Continued
CPU Sockets
There are two CPU sockets: a PQFP and a ZIF socket. The ZIF socket is the upgrade socket. If both the
PQFP and ZIF sockets contain CPUs, the CPU in the ZIF socket will be the active CPU. 486DX, 486SX,
and SL Enhanced 486DX and 486SX CPUs can be used in the PQFP socket.
The Super Voyager VLB-III motherboard also will support future Intel processors with internal write-back
cache.
Programmable Crystal Oscillator
The Super Voyager VLB-III motherboard has a programmable crystal oscillator that supports all possible
motherboard frequencies.
Heat Sink
A heat sink is provided if the following CPUs are installed:
CPU Frequency
80486DX 50 MHz
80486DX2 50 MHz
80486DX2 66 MHz
80486DX4 66 MHz
75 MHz
100 MHz
Processor Speed
The Super Voyager VLB-III motherboard has two clock speeds: high and low. High clock speed is factory-
set to 25, 33, or 50 MHz. Low clock speed is achieved by adding the appropriate number of software
delays, depending on the speed of the processor, and emulates an IBM® AT running at approximately 8
MHz. Speed selection is through the turbo switch or the keyboard. Press <Ctrl> <Alt> <+> for high speed
and <Ctrl> <Alt> <-> for low speed.