Asus P4P800 - Manual (Page 90)

4-16 Chapter 4: BIOS Setup
If you are using an unlocked CPU, the item CPU Ratio appears under
the AI Overclock Tuner item. You may select your desired ratio from
the available options.
CPU Ratio [12]
This field sets the ratio between the CPU Core Clock and the Front Side
Bus (FSB) Frequency.
If an invalid ratio is set in CMOS, the actual and setpoint values may
differ.
Select Screen
Select Item
+- Change Option
F1 General Help
F10 Save and Exit
ESC Exit
AI Overclock Tuner [Manual]
CPU External Frequency (MHz) [100]
CPU Ratio
[12]
DRAM Frequency [Auto]
AGP/PCI Frequency (MHz) [Auto]
CPU VCore Offset to .IV [Disabled]
DDR Reference Voltage [Auto]
AGP VDDQ Voltage [1.50V]
Performance Mode [Auto]
Configure System Frequency/Voltage
When you set the AI Overclocking Tuner item to [Manual], the related
overclocking items appear.
CPU External Frequency (MHz) [XXX] (value is auto-detected)
Indicates the frequency sent by the clock generator to the system bus and
PCI bus. The bus frequency (external frequency) multiplied by the bus
multiple equals the CPU speed. The value of this item is auto-detected by
BIOS and is not manually configurable. The values range from 100 to 400.
Refer to the following table for the correct Front Side Bus and CPU
External Frequency settings.
Performance Mode [Auto]
Allows enhanced system performance. Setting to [Turbo] may cause the
system to become unstable. If this happens, revert to the default setting
[Auto]. Configuration options: [Auto] [Standard] [Turbo]
Front Side Bus CPU External Frequency
FSB 800 200 MHz
FSB 533 133 MHz
FSB 400 100 MHz
Table 4.4.1 FSB/CPU External Frequency Synchronization