486-50 SPECS

        MODEL NUMBER: MD4-5061
         DESCRIPTION: 486DX-50 main board
      IDENTIFICATION: "30-000232-01" or "486IB-B-5-0"
                SIZE: Baby AT (8.6 x 13 in.)
             CHIPSET: SIS
                BIOS: AMI
              MEMORY: 1/2/4/8/16/32MB SIMM RAM (70ns) (no size mixing)
               CACHE: 64KB  = eight 8Kx8 SRAMs (25ns)
                      128KB = four 32Kx8
                      256KB = eight 32Kx8*
     CACHE ALGORITHM: Write-back or write-through direct-mapped
               SLOTS: Eight 16-bit
         PERFORMANCE: Landmark V1.14 = 227.7, Power Meter V1.7 = 22.3
       COMPATIBILITY: IBM PC/AT
             BATTERY: Discrete
SUPPORTED PROCESSORS: 486DX-33/50 (33,50MHz osc), 486SX-20/25
             SOCKETS: Weitek 4167 math coprocessor
 RAM BANK 0 LOCATION: Innermost 4 sockets
             MADE IN: Taiwan

J1: External battery connector
JP2: 1-2 = 8042 clock selectable by BIOS; 2-3 = 7.159MHz 8042 clock
JP3: 1-2 = normal; 2-3 (temporary) = CMOS clear
CPU type-----JP5----JP6----JP7
    486DX    1-2    1-2    short
    486SX    2-3    2-3    open
    487SX    1-2    2-3    short
JP8: 1-2 = internal power good signal*; 2-3 = external (from power supply)
Cache size-----JP9----JP10---JP11---JP12---JP13---JP14---JP15
    64KB       1-2    2-3    1-2    1-2    1-2    1-2    1-2
    128KB      2-3    1-2    1-2    2-3    1-2    2-3    1-2
    256KB      2-3    2-3    2-3    2-3    2-3    2-3    2-3
JP16: 1-2 = 486DX-33/50 or 486SX-25; 2-3 = 486SX-20
Color/mono: Short = CGA; open = mono (EGA/VGA: doesn't matter)
Turbo switch: Short = high speed or keyboard control; open = low speed

NOTES:
1) For 50MHz, set advanced chipset setup as follows (pp 3-14 & 3-15):
    DRAM speed option          = slowest
    Cache write cycle option   = 3T
    Cache read cycle option    = 2T
    Bus clock frequency select = 1/6 ACLK