BIOS Settings - Hardware Device Settings / "CPU Soft Menu"



The newest rage in motherboard design is the so-called 
"jumperless" motherboard. While this name is an 
exaggeration--these boards do have jumpers, just fewer of them 
than a regular motherboard--the idea is sound: to move many of 
the low-level hardware selection functions from hardware jumpers 
to regular BIOS settings, accessed through a BIOS settings group 
sometimes called a "CPU soft menu". Abit has popularized this 
type of motherboard.

This section describes the settings that are found in this setup 
group on jumperless motherboards. Regular jumpered motherboards 
will of course not have a section of this sort in their 
BIOS setup.

	Warning: Setting the values in this section incorrectly 
can possibly damage your processor or other hardware.


CPU Name/Type

The BIOS will automatically detect and display the type of CPU in 
the PC, including the manufacturer and family name (e.g., "Intel 
Pentium", "AMD K6"). This value cannot be changed.


CPU Operating Speed

This setting allows you to select the operating speed of your 
processor directly. When you set this value, the BIOS will 
automatically set the "External Clock" and "Multiplier Factor" 
values for you, and lock them so they cannot be changed. For 
example, setting this value to "166" will set the external clock 
to 66 MHz, and the multiplier to 2.5X. To manually control the 
external clock and multiplier factor values, you must set this 
parameter to "User Defined".


External Clock

This setting controls the clock speed of the memory bus on the 
motherboard, and is normally 50, 60, 66 or 75 MHz. The internal 
processor speed is the product of the external clock speed of the 
motherboard and the multiplier used by the processor.

	Note: When the CPU Operating Speed parameter is set to a 
specific number, the External Clock parameter is computed by the 
BIOS and this setting is disabled.


Multiplier Factor

This setting controls the multiplier that is used to determine the 
internal clock speed of the processor relative to the external or 
motherboard clock speed. The usual values are 1.5X, 2X, 2.5X, 3X, 
3.5X and so on.

	Note: When the CPU Operating Speed parameter is set to a 
specific number, the External Clock parameter is computed by the 
BIOS and this setting is disabled.


CPU Power Plane

This setting controls how the voltage for the processor is to be 
specified. There are three different options. Depending on which 
one you select, the BIOS will change the other available 
voltage settings: 

	Single Voltage: This option is, of course, for 
	conventional processors that use a single voltage only. 
	Selecting this option enables the "Plane Voltage" setting 
	and disables the other voltage settings. 

	Dual Voltage: Select this option for processors that use 
	split-rail or dual voltage. This option enables the "I/O 
	Plane Voltage" and "Core Plane Voltage" settings. 

	Via CPU Marking: Selecting this option will allow you to 
	specify the CPU marking (specification) code for your 
	processor, which will tell the BIOS how to set the 
	voltage automatically. This is done using the "CPU 
	Marking" BIOS setting, and the other voltage settings 
	are disabled. The code is usually a five-character code 
	such as "SY016" that is found on the top surface or 
	bottom surface of the CPU. 


Plane Voltage

When the CPU Power Plane is set to "Single Voltage", this 
parameter allows you to choose what the voltage should be. This 
should be set to the correct voltage for your particular CPU <../../../cpu/char/power_Specifics.htm>. When CPU Power Plane 
is set to anything other than "Single Voltage", this setting 
will not be present.


I/O Plane Voltage

When the CPU Power Plane is set to "Dual Voltage", this parameter 
allows you to choose what the I/O or external voltage should be. 
When CPU Power Plane is set to anything other than "Dual 
Voltage", this setting will not be present.


Core Plane Voltage

When the CPU Power Plane is set to "Dual Voltage", this 
parameter allows you to choose what the core or internal voltage 
should be. When CPU Power Plane is set to anything other than 
"Dual Voltage", this setting will not be present.


CPU Marking

When the CPU Power Plane is set to "Via CPU Marking", this 
parameter allows you to choose what the marking code is for your 
CPU, which will tell the BIOS what voltage(s) the CPU requires. 
You may not know what your code is, or it may not be listed, so 
you may want to use the manual settings ("Single Voltage" or 
"Dual Voltage") in this case. When CPU Power Plane is set to 
anything other than "Via CPU Marking", this setting will not be 
present.
