User Guide

Hardware Installation
2-7
2.2.5 AGP Ratio
JP23
1-2
3-4
5-6
DC/Host Ratio
Auto (default)
2/3
1/1
To improve system performance, this motherboard
has implemented this jumper for setting the ratio of
the display cache and CPU external frequency.
JP23
1
3
5
2
4
6
Auto
(Default)
JP23
1
3
5
2
4
6
2/3
JP23
1
3
5
2
4
6
1/1
There is a "66/100" signal pin from CPU for ZX/BX chipset to automatically
identify AGP clock, this is important for jumperless design. When a 66MHz
Pentium II CPU is used, the north bridge will synchronize the CPU external
frequency and the AGP bus frequency. Therefore, when you set the CPU
external frequency to 100MHz, the AGP bus will also runs at 100MHz.
With 100MHz Pentium II CPU, the north bridge automatically set AGP frequency
to 2/3 AGP frequency. In other words, the AGP card will still runs at 66MHz while
the CPU is running at 100MHz external frequency.
Except Auto setting, you may also set this jumper to 2/3 or 1/1. Below is a table
for better understanding:
CPU Type 66/100 signal Bus clock AGP clock JP23
66MHz Low 66MHz 66MHz 1-2
66MHz Low 100MHz 100MHz 1-2
66MHz Low 100MHz 66MHz 3-4
100MHz High 100MHz 66MHz 1-2
100MHz High 100MHz 66MHz 3-4
100MHz High 100MHz 100MHz 5-6
100MHz High 133MHz 88.6MHz 1-2
100MHz High 133MHz 88.6MHz 3-4
100MHz High 133MHz 133MHz 5-6
Warning: The specification of AGP has a maximum of
100Mhz clock. A higher setting may cause the system
damage.