MS-5146 version 1.03

1. CPU Core Speed Derivation Procedure
The 4 CPU clock frequencies that the system supports are 50MHz, 55MHz, 60MHz and 66.6MHz (To adjust SW1 pin 3 and 4). See the following chart to set the different Host Clock Frequencies.

SW1
CPU Speed
3
4
5
6
Clock
Clock
ON
ON
OFF
ON/OFF
50MHz
25MHz
OFF
ON
OFF
ON/OFF
55MHz
27.5MHz
ON
OFF
OFF
ON/OFF
60MHz
30MHz
OFF
OFF
OFF
ON/OFF
66.6MHz
33MHz
ON
OFF
ON
ON/OFF
75MHz
33MHz
OFF
OFF
ON
ON/OFF
75MHz
37.5MHz
Note: SW1 Pin 6 is for setting Linear or Toggle mode. Linear mode Pin6 is On. Toggle mode Pin 6 is off.

2. The DIP Switch SW1 (1,2) 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
Core/Bus Ratio
ON
ON
5 / 2
OFF
ON
3 / 1
ON
OFF
2 / 1
OFF
OFF
3 / 2

3. CPU Voltage Setting: JV2-JV4
V I/O
Vcore
JV1
JV2
JV4
JV3
3.38
3.38
OPEN
OPEN
OPEN
OPEN
1-OPEN
2-SHORT
3-SHORT
3.52
3.52
SHORT
OPEN
OPEN
OPEN
1-OPEN
2-SHORT
3-SHORT
3.3
3.0
OPEN
OPEN
SHORT
OPEN
1-SHORT
2-SHORT
3-OPEN
3.3
2.8
SHORT
SHORT
OPEN
OPEN
1-SHORT
2-SHORT
3-OPEN
3.3
2.9
SHORT
OPEN
OPEN
SHORT
1-SHORT
2-SHORT
3-OPEN
4. CPU Speed and Voltage Setting: SW1 & JV2-JV4
To adjust the speed and voltage of the CPU, you must know the specification of your CPU (always ask the vendor for the CPU specification) then look at Table 5 (Intel P54C/P55C-MMX), Table 6 (Cyrix 6x86) and Table 7 (AMD 5k86) for proper setting.

5. Intel P54C (Pentium), P55C (MMX) CPU:

CPU Type
Cpu Voltage
CPU Speed
VI/O
Vcore
JV2~JV4(from left to right)
(Top to Down)
SW1
1 2 3 4 5 6
P54C-75
3.38
JK1
1,2 - Short
3,4 - Open
5,6 - Short
JV2-JV4- all Open
J3-Short (2,3)
OFF OFF ON ON OFF OFF
P54C-90
3.38
JV2-JV4- all Open
J3-Short (2,3)
OFF
OFF
ON
OFF
OFF
OFF
3.52
JV2-Short (first)
JV2-Open (Second)
JV4-All Open
JV3-Short (2,3)
P54C-100
3.38
JV2-JV4 - ALL OPEN
JV3-SHORT (2,3)
OFF
OFF
OFF
OFF
OFF
OFF
P54C-120
3.38
ON
OFF
ON
OFF
OFF
OFF
P54C-133
3.38/3.52
JV2-JV4-
all Open
J3-Short (2,3)
JV2-Short (first)
JV2-Open (Second)
JV4-All Open
JV3-Short (2,3)
ON
OFF
OFF
OFF
OFF
OFF
P54C-150
3.38/3.52
ON
ON
ON
OFF
OFF
OFF
P54C-166
3.38/3.52
ON
ON
OFF
OFF
OFF
OFF
P55C-166
3.33
2.8
JV2-SHORT (1,2)
JV4-ALL OPEN
JV3-SHORT (1,2)
P54C-200
3.52
V2-Short (first)
JV2-Open (Second)
JV4-All Open
JV3-Short (2,3)
OFF
ON
OFF
OFF
OFF
OFF
P55C-200
3.33
2.8
JV2-SHORT (1,2)
JV4-ALL OPEN
JV3-SHORT (1,2)

Note: JK1 is only use for 75MHz. Using other CPU type must leave the JK1 open.
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6. Cyrix 6x86 CPU
Cyrix 6x86CPU uses P to rate the speed of its processor base on Intel CPU core speed, for example P120+ (100Mhz) has 120MHz core speed of Intel but has 100MHz core speed in Cyrix. Cyrix 6x68 CPU should always uses a more powerful fan (ask vendor for proper colling fan).

CPU Type
Cpu Voltage
CPU Speed
VI/O
Vcore
JV2~JV4(from left to right)
(Top to Down)
SW1
1
2
3
4
5
6
P120+ (100MHz)
3.52
JK1
1,2 - Short
3,4 - Open
5,6 - Short
JV2-Short (first)
JV2-Open (Second)
JV4-All Open
JV3-Short (2,3)
OFF ON ON ON OFF ON
P133+ (110MHz)
JV2-Short (first)
JV2-Open (Second)
JV4-All Open
JV3-Short (2,3)
ON
OFF
OFF
ON
OFF
ON
P150+ (120MHz)
JV2-All Short
JV4-All Open
JV3-Short (1,2)
ON
OFF
ON
OFF
OFF
ON
P166+
(133MHz)
3.4 2.8
ON
OFF
OFF
OFF
OFF
ON
P200+ (150MHz)
3.38/3.52
JV2-Short (first)
JV2-Open (Second)
JV4-All Open
JV3-Short (2,3)
ON OFF ON OFF ON ON
Note: The Cyrix CPU can be set to Linear or Toggle mode, But we recommend that you use the linear mode so the Pin 6 is On.
P200+(150MH) - PCI clock is 33MHz.

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7. AMD 5K86CPU
AMD 5K86 CPU uses PR to rate the speed of its processor base on Intel CPU core speed, for example PR133+(100MHz) has 133MHz core speed of Intel but has 100MHz core speed in AMD 5K86CPU.
CPU Type
Cpu Voltage
CPU Speed
VI/O
Vcore
JV2~JV4(from left to right)
(Top to Down)
SW1
1
2
3
4
5
6
PR75
3.52
JK1
1,2 - Short
3,4 - Open
5,6 - Short
JV2-Short (first)
JV2-Open (Second)
JV4-All Open
JV3-Short (2,3)
OFF OFF ON ON OFF OFF
PR90 & PR120
JV2-Short (first)
JV2-Open (Second)
JV4-All Open
JV3-Short (2,3)
OFF
OFF
ON
OFF
OFF
OFF
PR100 & PR133
OFF
OFF
OFF
OFF
OFF
OFF
PR166
ON
ON
OFF
OFF
OFF
OFF
Note: JK1 is only use for 75MHz. Using other CPU type must leave the JK1 open

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