Selecting The Cpu Frequency - AOpen AX3L User Manual

Hardware Installation

2.2.1 Selecting the CPU Frequency

Celeron PPGA VID signal and SMbus clock generator provide CPU voltage
auto-detection and allow user to set CPU frequency through CMOS setup, no
jumper or switch is needed. The correct CPU information is saved into
EEPROM, with these technologies, the disadvantages of Pentium base
jumper-less design are eliminated. There will be no worry of wrong CPU
voltage detection and no need to re-open the housing if CMOS battery loss.
The CPU frequency selection is set by going into:
BOIS Setup Chipset Features Setup
(The possible setting is 66.8, 68.5, 70, 73.8, 75, 78.5, 83.3 MHz)
BOIS Setup Chipset Features Setup
(The possible setting is 1.5x, 2x, 2.5x, 3x, 3.5x, 4x, 4.5x, 5x, 5.5x, 6x, 6.5x, 7x, 7.5x,
and 8x)
Core frequency = Ratio * External bus clock
INTEL Celeron PPGA
Celeron PPGA 300A
Celeron PPGA 333
Celeron PPGA 366
Celeron PPGA 400
Celeron PPGA 433
Warning: INTEL 440LX chipset supports maximum 66MHz external
CPU bus clock, the higher clock settings are for internal test only. These
settings exceed the specification of LX chipset, which may cause
serious system damage.
2-4
CPU Clock Ratio
CPU Core Frequency
300MHz=
333MHz=
366MHz=
400MHz=
433MHz=
CPU Clock Frequency
Ratio External Bus Clock
4.5x 66MHz
5x 66MHz
5.5x 66MHz
6x 66MHz
6.5x 66MHz