MS-5153

CPU Speed Setting: SW1
To adjust the speed and voltage of the CPU, you must know the specifications of your CPU (always ask the vendor for CPU specifications). Then refer to table 5 (Intel Prossors), Table 6 (Cyrix Processors), and Table 7 (AMD Processors) for proper setting.

1. The mainboard suuports different clock frequencies adjusted by SW1 pin 4,5, and 6. See the following chart to set the different Host Clock Frequencies.

SW1
CPU
4
5
6
Clock
ON
ON
OFF
55MHz
ON
OFF
OFF
60MHz
OFF
OFF
OFF
66MHz
OFF
ON
OFF
75MHz
OFF
OFF
ON
68.5MHz

Special CPU Clock:
SW1
CPU
4
5
6
Clock
OFF
OFF
OFF
50MHz
OFF
OFF
ON
69.5MHz
OFF
ON
ON
78MHz
ON
ON
OFF
83.3MHz
ON
OFF
ON
85.5MHz
ON
OFF
OFF
100MHz
NOTE: If you are going to use the special CPU clock, then you must short JRMS3
The JRMS3 jumper is located next to the SW1 DIP switch.

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.
SW1
CPU
1
2
3
Core/Bus Ratio
OFF
OFF
OFF
1.5/3.5
ON
OFF
OFF
2
ON
ON
OFF
2.5/1.75
OFF
ON
OFF
3

3. CPU Voltage: The mainboard voltage regulators can automatically detect and switch between Single and Dual voltage. It can detect single voltage ranging from 3.38 volts to 3.52 volts. And dual voltage ranging from 2.0 volts to 3.2 volts.

4.Intel Processors: Intel Processors
Intel Pentium Processor with MMX Technology

CPU Type
CPU Speed
SW1
1
2
3
4
5
6
90MHz
OFF
OFF
OFF
ON
OFF
OFF
100MHz
OFF
OFF
OFF
OFF
OFF
OFF
120MHz
ON
OFF
OFF
ON
OFF
OFF
133MHz
ON
OFF
OFF
OFF
OFF
OFF
150MHz
ON
ON
OFF
ON
OFF
OFF
166MHz
ON
ON
OFF
OFF
OFF
OFF
200MHz
OFF
ON
OFF
OFF
OFF
OFF
Intel Pentium Processors with MMX technology
166MHz
ON
ON
OFF
OFF
OFF
OFF
200MHz
OFF
ON
OFF
OFF
OFF
OFF
233MHz
OFF
OFF
OFF
OFF
OFF
OFF
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5. Cyrix Processors: Cyrix 6x86 processor uses PR to rate the speed of their processors based on Intel Pentium processor core speed. For example PR150 (120MHz)has 150Mhz core speed of Intel Pentium processor but has 120MHz core speed in Cyrix. Cyrix 6x86 processor should always use a more powerful fan (ask vendor for proper cooling fan).
Cyrix 6x86 Processors:
CPU Type
CPU Speed
SW1
1
2
3
4
5
6
PR133 (110MHz)
ON
OFF
OFF
ON
ON
OFF
PR150 (120MHz)
ON
OFF
OFF
ON
OFF
OFF
PR166 (133MHz)
ON
OFF
OFF
OFF
OFF
OFF

Cyrix 6x86L Processors:
166MHz
ON
OFF
OFF
OFF
OFF
OFF

Cyrix 6x86MX Processors
PR166 (60x2.5)
ON
ON
OFF
ON
OFF
OFF
PR166 (66x2)
ON
OFF
OFF
OFF
OFF
OFF
PR200
(66x2.5)
ON
ON
OFF
OFF
OFF
OFF
PR200
(75x2)
ON
OFF
OFF
OFF
ON
OFF
PR233
(66x3)
OFF
ON
OFF
OFF
OFF
OFF
PR233
(75x2.5)
ON
ON
OFF
OFF
ON
OFF
PR266 (66x3.5)
OFF
OFF
OFF
OFF
OFF
OFF
PR266 (75x3)
OFF
ON
OFF
OFF
ON
OFF
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6. AMD Processor: AMD K5 processor uses PR to rate the speed of their processors based on Intel Pentium processor core speed. For example PR133 (100MHz) has 133 MHz core speed of Intel Pentium processor but has 100MHz core speed in AMD K5 processor.
AMD K5 Processors:
CPU Type
CPU Speed
SW1
1
2
3
4
5
6
PR90 (90MHz)
OFF
OFF
OFF
ON
OFF
OFF
PR100 (100MHz)
OFF
OFF
OFF
OFF
OFF
OFF
PR120 (90MHz)
ON
OFF
OFF
ON
OFF
OFF
PR133 (100MHz)
ON
OFF
OFF
OFF
OFF
OFF
PR150 (105MHz)
ON
ON
OFF
ON
OFF
OFF
PR166 (116.7MHz)
ON
ON
OFF
OFF
OFF
OFF
AMD K6 Processors:
166MHz
ON
ON
OFF
OFF
OFF
OFF
200MHz
OFF
ON
OFF
OFF
OFF
OFF
233MHz
OFF
OFF
OFF
OFF
OFF
OFF
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