Cpu Core Speed Derivation Procedure - MSI ATX BX1 User Manual

2.1-2 CPU Core Speed Derivation Procedure

1. The DIP Switch SW1 (1, 2, 3, and 4) is used to set the Core/Bus (Fraction)
ratio of the CPU. The actual core speed of the CPU is the Host Clock
Frequency multiplied by the Core/Bus ratio. For example:
If
then
1
ON OFF
ON ON
ON OFF
ON ON
ON OFF
ON ON
ON OFF
OFF ON
OFF OFF
OFF ON
OFF OFF
OFF ON
Note: a. The CPU Bus Frequency is set at 66MHz or 100MHz by CPU
default.
b. If the mainboard support CPU Plug & Play, disregard this table
and go directly to BIOS Special Features Setup to set the CPU
speed.
2. The PCI Bus Clock is fixed at 33MHz.
CPU Clock
Core/Bus ratio
CPU core speed =
2 3
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
= 66MHz
= 3.5
Host Clock x Core/Bus ratio
= 66MHz x 3.5
= 233MHz
4 Core/Bus Ratio
ON
ON
ON
OFF
OFF
OFF
OFF
ON
ON
ON
ON
OFF
2-16
2.5
3
3.5
4
4.5
5
5.5
6
6.5
7
7.5
8