Cpu Core Speed Derivation Procedure - MSI MS-5191 Manual

2.1-2 CPU Core Speed Derivation Procedure

1. The DIP Switch SW1 (4, 5, & 6) is used to adjust the CPU clock frequency.
2. The DIP Switch SW1 (1, 2, and 3) 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 CPU Clock
Core/Bus ratio
then CPU core speed
OFF
OFF
ON
ON
OFF
OFF
ON
ON
SW1
4 5
OFF OFF
ON OFF
OFF ON
OFF OFF
OFF ON
ON ON
ON OFF
SW1
1 2
OFF
ON
ON
OFF
OFF
ON
ON
OFF
CPU
6 Clock
OFF 100MHz
OFF 95MHz
OFF 83MHz
ON 75MHz
ON 66MHz
ON 60MHz
ON 68MHz
= 66MHz
= 3/2
= Host Clock x Core/Bus ratio
= 66MHz x 3/2
= 100MHz
3 Core/Bus Ratio
ON
ON
ON
ON
OFF
OFF
OFF
OFF
2-2
CPU
5.5x
5x
4.5x
4x
3.5x
3x
2.5x
2x