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SCI 486SX/DX SYSTEM BOARD
SCI SYSTEMS, INC.
SCI 486SX/DX SYSTEM BOARD
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Processor
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80486SX/80486DX
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Processor Speed
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25/33MHz
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Chip Set
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OPTI
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Max. Onboard DRAM
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64MB
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Cache
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64/256KB
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BIOS
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Unidentified
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Dimensions
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330mm x 218mm
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I/O Options
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Floppy drive interface, IDE interface, parallel port, PS/2 mouse port, serial ports (2), VGA port
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NPU Options
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None
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CONNECTIONS
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Purpose
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Location
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Purpose
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Location
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PS/2 mouse port
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J1
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IDE interface LED
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J23
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IDE interface
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J5
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Reset switch
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J24
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Floppy drive interface
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J6
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Speaker
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J25
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Parallel port
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J8
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Power LED & keylock
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J26
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Serial port 2
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J9
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VGA port
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J27
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Serial port 1
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J10
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USER CONFIGURABLE SETTINGS
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Function
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Jumper/Switch
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Position
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»
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Monitor type select color
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W1
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pins 1 & 2 closed
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Monitor type select monochrome
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W1
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pins 2 & 3 closed
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»
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CMOS memory normal operation
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W2
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pins 1 & 2 closed
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CMOS memory clear
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W2
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pins 2 & 3 closed
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»
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SYSCLK enabled
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W3
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pins 2 & 3 closed
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SYSCLK/2 enabled
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W3
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pins 1 & 2 closed
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»
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On board VGA enabled
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W10
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pins 1 & 2 closed
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On board VGA disabled
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W10
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pins 2 & 3 closed
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»
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Video horizontal scan rate select 31.5 kHz
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SW1/5
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On
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Video horizontal scan rate select 40kHz
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SW1/5
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Off
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»
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Video memory select 512KB
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SW1/6
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On
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Video memory select 1MB
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SW1/6
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Off
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DRAM CONFIGURATION
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Size
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Bank 0
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Bank 1
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Bank 2
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Bank 3
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1MB
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(1) 256K x 36
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NONE
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NONE
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NONE
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2MB
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(1) 256K x 36
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(1) 256K x 36
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NONE
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NONE
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4MB
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(1) 1M x 36
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NONE
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NONE
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NONE
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5MB
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(1) 256K x 36
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(1) 1M x 36
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NONE
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NONE
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6MB
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(1) 256K x 36
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(1) 256K x 36
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(1) 1M x 36
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NONE
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8MB
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(1) 1M x 36
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(1) 1M x 36
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NONE
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NONE
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9MB
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(1) 256K x 36
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(1) 1M x 36
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(1) 1M x 36
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NONE
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10MB
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(1) 256K x 36
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(1) 256K x 36
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(1) 1M x 36
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(1) 1M x 36
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12MB
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(1) 1M x 36
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(1) 1M x 36
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(1) 1M x 36
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NONE
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13MB
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(1) 256K x 36
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(1) 1M x 36
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(1) 1M x 36
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(1) 1M x 36
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16MB
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(1) 1M x 36
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(1) 1M x 36
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(1) 1M x 36
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(1) 1M x 36
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16MB
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(1) 4M x 36
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NONE
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NONE
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NONE
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20MB
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(1) 1M x 36
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(1) 4M x 36
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NONE
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NONE
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20MB
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(1) 4M x 36
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(1) 1M x 36
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NONE
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NONE
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24MB
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(1) 1M x 36
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(1) 1M x 36
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(1) 4M x 36
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NONE
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24MB
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(1) 1M x 36
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(1) 4M x 36
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(1) 1M x 36
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NONE
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24MB
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(1) 4M x 36
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(1) 1M x 36
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(1) 1M x 36
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NONE
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28MB
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(1) 1M x 36
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(1) 1M x 36
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(1) 4M x 36
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(1) 1M x 36
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28MB
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(1) 1M x 36
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(1) 4M x 36
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(1) 1M x 36
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(1) 1M x 36
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28MB
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(1) 4M x 36
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(1) 1M x 36
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(1) 1M x 36
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(1) 1M x 36
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32MB
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(1) 4M x 36
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(1) 4M x 36
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NONE
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NONE
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36MB
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(1) 1M x 36
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(1) 1M x 36
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(1) 1M x 36
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NONE
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36MB
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(1) 1M x 36
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(1) 1M x 36
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(1) 1M x 36
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NONE
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36MB
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(1) 4M x 36
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(1) 4M x 36
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(1) 1M x 36
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NONE
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40MB
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(1) 1M x 36
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(1) 1M x 36
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(1) 4M x 36
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(1) 4M x 36
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40MB
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(1) 1M x 36
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(1) 4M x 36
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(1) 4M x 36
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(1) 1M x 36
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40MB
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(1) 4M x 36
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(1) 1M x 36
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(1) 4M x 36
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(1) 1M x 36
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40MB
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(1) 4M x 36
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(1) 4M x 36
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(1) 1M x 36
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(1) 1M x 36
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DRAM CONFIGURATION (CON’T)
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Size
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Bank 0
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Bank 1
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Bank 2
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Bank 3
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48MB
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(1) 4M x 36
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(1) 4M x 36
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(1) 4M x 36
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NONE
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52MB
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(1) 1M x 36
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(1) 4M x 36
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(1) 4M x 36
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(1) 4M x 36
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52MB
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(1) 4M x 36
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(1) 1M x 36
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(1) 4M x 36
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(1) 4M x 36
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52MB
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(1) 4M x 36
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(1) 4M x 36
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(1) 4M x 36
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(1) 1M x 36
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64MB
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(1) 4M x 36
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(1) 4M x 36
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(1) 4M x 36
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(1) 4M x 36
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CACHE CONFIGURATION
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Size
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Bank 0
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Bank 1
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TAG
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64KB
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(4) 8K x 8
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(4) 8K x 8
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(2) 16K x 4
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256KB
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(4) 32K x 8
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(4) 32K x 8
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(2) 16K x 4
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CACHE JUMPER CONFIGURATION
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Size
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W4
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W5
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W9
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W11
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64KB
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pins 2 & 3 closed
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pins 2 & 3 closed
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pins 2 & 3 closed
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pins 2 & 3 closed
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256KB
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pins 1 & 2 closed
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pins 1 & 2 closed
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pins 1 & 2 closed
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pins 2 & 3 closed
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CPU TYPE CONFIGURATION
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Type
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W6
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W7
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W8
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486SX
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pins 2 & 3 closed
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pins 2 & 3 closed
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N/A
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487SX
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pins 1 & 2 closed
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pins 1 & 2 closed
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pins 1 & 2 closed
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486DX
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pins 1 & 2 closed
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pins 1 & 2 closed
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pins 2 & 3 closed
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VIDEO CONFIGURATION (800 X 600)
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Refresh rate
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SW1/1
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SW1/2
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60Hz
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Off
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On
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56Hz
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Off
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Off
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56Hz
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On
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On
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72Hz
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On
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Off
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VIDEO CONFIGURATION (1024 X 768)
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Refresh rate
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SW1/3
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SW1/4
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Interlaced
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Off
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Off
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60Hz
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Off
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On
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70Hz
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On
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Off
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72Hz
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On
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On
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VIDEO MEMORY CONFIGURATION
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Size
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Bank 0
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Bank 1
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512KB
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(4) 256K x 4
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NONE
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1MB
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(4) 256K x 4
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(4) 256K x 4
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Note: Bank 0 is factory installed and is not configurable.
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