Albatron Technology PX845PEV-800 - Manual (Page 13)

Albatron Anniversary Special Edition PX845PEV-800
10
Formulas
CPU Speed = CPU Clock Ratio * CPU Host Frequency
DDR Speed = DDR: CPU Ratio * CPU Host Frequency
(The CPU Clock Ratio is usually locked by the CPU manufacturer which means it will not be
displayed. You can only adjust the CPU Host Frequency to change the CPU speed. For more
details, please refer to the Frequency / Voltage Control section in Chapter 2.)
If you do not adjust the option, then the CPU Host Frequency will be equal of default CPU
Host Frequency. Or you can adjust the “CPU Host Frequency” and “DDR: CPU Ratio” in the
BIOS Setup Utility for overclocking the CPU and DDR RAM, but we do not guarantee that
damage will or will not occur.
Overclocking example (to FSB 800): have an Intel ® Pentium4 Host Frequency 1.7 GHz CPU
(133MHz, 13 Ratio) and a DDR 400 RAM module plugged on Albatron PX845PEV-800
mainboard. Adjust the “CPU Host Frequency” to 200 and the “DDR: CPU Ratio” to 2.00
(default) in the BIOS Utility. Then the result: the CPU Speed will be 2.6 GHz, and DDR Speed
will be DDR 400. (Suggestion: if you adjust your CPU Host Frequency over 166, disable the
“Fixed AGP/PCI Output Freq” item.)
Note: The AGP and PCI frequencies are both calculated from the Default CPU Host frequency
according to the table below. To determine your frequencies, first locate the row that
corresponds to the “Default CPU Host frequency”. Then, calculate the AGP and PCI
frequencies according to the formulas in the adjacent cells.
Default CPU Host frequency PCI frequency AGP frequency
100 MHz CPU Host frequency ÷ 3 CPU Host frequency * (2/3)
133 MHz CPU Host frequency ÷ 4 CPU Host frequency * (2/4)
200 MHz CPU Host frequency ÷ 5 CPU Host frequency * (2/5)
E.g.: If your “Default CPU Host frequency” is 133, then the AGP frequency will be 66 MHz
and the PCI frequency will be 33 MHz.
Watch Dog Timer
This mainboard comes with a special feature called “Watch Dog Timer” which is used to
detect when the system is unable to boot using the manual over-clocking configurations. After
you power on the system, BIOS will check the last system POST status. If it was successful,
BIOS will enable the “Watch Dog Timer” feature and set the CPU frequency values to the user
configured values stored in the BIOS. If unsuccessful the “Watch Dog Timer” will reboot the
system.
On most systems you would need to remove the cover of your system and re-jumper the clear
CMOS switches on the mainboard when your system encounters over-clocking problems. With
the “Watch Dog Timer”, overclocking settings will be automatically cleared and reset.
Before Overclocking
Please make sure your system components are capable of overclocking.
If you are not familiar with the overclocking, we strongly recommend that you to
set the clock to the default settings.