Configuring External Clock Speed & Factor; Configuring Cpu Voltage - ECS P5TX-Apro User Manual

P5TX–Apro User's Manual
3: Reconfiguring Your Mainboard – 3.10
Configuring External Clock Speed & Factor
To configure the board for a CPU's internal clock speed, you
have to set the external clock speed (sometimes referred to as the
bus speed) and the clock factor so that the result is the internal
clock speed of the CPU you are installing. For example, the de-
fault setting for these is:
66.6MHZ [external clock] x 2.0 [clock factor] =133.2MHz
or, an effective setting of 133MHz.
Since the internal clock speed the CPU is supposed to operate
at is fixed, the two factors, external clock and clock factor, are the
variables. The CPU manufacturer or vendor's information should
tell you what these factors should be.
P Rated CPUs
Cyrix, IBM and AMD all make Pentium
performance rated at an Intel Pentium
tually have a slower internal clock speed. This 'P' rating is used
to indicate the CPU's performance rather than its internal clock
speed. For example, the Cyrix/IBM P166 has an actual internal
clock speed of 133MHz. If you install a CPU of this type, make
sure you set the mainboard for the actual internal clock speed of
the CPU, not its P rating.

Configuring CPU Voltage

The CPU voltage specification should also be provided in in-
formation from the manufacturer or vendor. Standard Pentium
CPUs are single voltage. MMX Pentiums
should set the CPU Voltage jumpers according to the specifica-
tions you get with the CPU.
® -class CPUs that are
®
equivalent speed but ac-
® are dual-voltage. You
®