Appendix A

Specifications

CPU and Memory

32-bit CPU

4SX/25C: Intel i486SX, 25 MHz microprocessor in open

 

PGA-type CPU socket; can be upgraded with optional

 

487SX/25 math coprocessor or Intel ODP486-25

 

OverDrive processor

 

4DX/33C: Intel i486DX, 33 MHz microprocessor in

 

PGA-type CPU socket; can be upgraded with optional

 

Intel ODP486-33 OverDrive processor

 

4DX2/50C: Intel i486DX2, 50 MHz microprocessor in

 

PGA-type CPU socket

 

 

System speed

High and low speeds available; high speed is

 

CPU-dependent (25 MHz, 33 MHz, or 50 MHz), low

 

speed is simulated 8 MHz speed; speed selection

 

through keyboard command or SETUP; 0 wait state

 

memory access at high speed

 

 

Memory

4MB RAM standard soldered on the system board;

 

expandable to 36MB (maximum) using 1 MB, 4MB. or

 

T6MB SIMMs: SlMMs must be 36-bit, 72-pin, fast-page

 

mode type with 70ns (or faster) access speed

 

 

ROM

128KB system BIOS, video BIOS, and SETUP code

 

located in EPROM on main system board

 

 

video RAM

512KB on main system board; expandable to 1 MB

 

 

Shadow RAM

Supports shadowing of system and video BIOS ROM

 

into RAM

 

 

Cache

8KB of internal cache (built into the microprocessor);

 

sockets for up to 256KB of SRAM external cache

 

(optional)

 

 

Math

On 486DX/33C. and 486DX2/50C systems, math

coprocessor

coprocessor built into the microprocessor; optional 487

 

upgrade available for 25 MHz system

 

 

Clock/

Real-time clock, calendar, and CMOS RAM socketed

calendar

on main system board with built-in battery backup

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S p e c i f i c a t i o n s A - 1