MS-5163

CPU Speed and Voltage Setting: SW1 AND SW2
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 4 (Intel Prossors), Table 5 (Cyrix Processors), and Table 6 (AMD Processors) for proper setting.

1.CPU Core Speed Derivation Procedure
The Switch SW1 (4&5) is used to adjusted the CPU clock frequency.

SW1
CPU
4
5
Clock
ON
ON
60MHz
OFF
ON
66MHz
ON
OFF
75MHz
OFF
OFF
83.3MHz

2. The Switch SW1 (1,2 &3) is used to set the Core/Bus (Fraction) ratio of the CPU.

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

3. CPU Voltage Setting: SW2

V I/O
Vcore
SW2
1
2
3
4
5
3.5
3.5
OFF
ON
ON
ON
ON
3.3
3.3
OFF
ON
ON
OFF
ON
3.3
3.2
OFF
ON
ON
OFF
OFF
3.3
2.9
OFF
ON
OFF
OFF
ON
3.3
2.8
OFF
ON
OFF
OFF
OFF
3.3
2.5
OFF
OFF
ON
OFF
ON
3.3
2.1
OFF
OFF
OFF
OFF
ON


4. Intel Processors: Intel Processors
Intel Pentium Processor with MMX Technology
CPU Type
CPU Voltage
CPU Speed
V I/O
Vcore
SW2
SW1
1
2
3
4
5
1
2
3
4
5
90MHz
3.38
OFF
ON
ON
OFF
ON
OFF
OFF
OFF
ON
ON
3.52
OFF
ON
ON
ON
ON
100MHz
3.38
OFF
ON
ON
OFF
ON
OFF
OFF
OFF
OFF
ON
120MHz
3.38
ON
OFF
OFF
ON
ON
133MHz
3.52
OFF
ON
ON
ON
ON
ON
OFF
OFF
OFF
ON
150MHz
3.52
ON
ON
OFF
ON
ON
166MHz
3.52
ON
ON
OFF
OFF
ON
200MHz
3.52
OFF
ON
OFF
OFF
ON
Intel Pentium Processors with MMX technology
166MHz 3.3 2.8 OFF ON OFF OFF OFF ON ON OFF OFF ON
200MHz OFF ON OFF OFF ON
233MHz OFF OFF OFF OFF ON
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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 6x86/6x86L Processors:
CPU Type
CPU Voltage
CPU Speed
V I/O
Vcore
SW2
SW1
1
2
3
4
5
1
2
3
4
5
6x86
PR150
3.5
OFF
ON
ON
ON
ON
ON
OFF
OFF
ON
ON
6X86
PR166
ON
ON
OFF
ON
ON
6x86L
PR166
3.3
2.8
OFF
ON
OFF
OFF
OFF
6x86
PR200
3.5
OFF ON ON ON ON
ON
ON
OFF
OFF
ON
6x86L
PR200
3.3
2.8
OFF
ON
OFF
OFF
OFF
Cyrix 6x86MX Processors
PR166 (60x2.5) 3.3 2.9 OFF ON OFF OFF ON ON ON OFF ON ON
PR200 (66x2.5) ON ON OFF OFF ON
PR233
(75x2.5)
ON ON OFF ON OFF
PR233
(66x3)
OFF ON OFF OFF ON
PR266
(75x3)
OFF ON OFF ON OFF
PR266
(66x3.5)
OFF OFF OFF OFF ON
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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 Voltage
CPU Speed
V I/O
Vcore
SW2
SW1
1
2
3
4
5
1
2
3
4
5
PR90
3.52
OFF
ON
ON
ON
ON
OFF OFF OFF ON ON
PR100 OFF OFF OFF
OFF
ON
PR120 ON OFF OFF ON ON
PR133 ON OFF OFF
OFF
ON
PR150 ON ON OFF ON ON
PR166 ON ON OFF OFF ON
AMD K6 Processors:
PR166
3.3 2.9 OFF ON OFF OFF ON ON ON OFF OFF ON
PR200 OFF ON OFF OFF ON
PR233 3.3 3.2 OFF ON ON OFF OFF OFF OFF OFF OFF ON
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