Epson 4000 - Manual (Page 15)

Video Memory
You can add video memory chips to your system board to
increase the video memory to 2MB and support higher video
resolutions with more colors.
Microprocessor
You can upgrade your system with these microprocessors:
486SX/33
486DX/33
486DX2/50
486DX2 /66.
Math Coprocessor
You automatically install a math coprocessor when you
upgrade your system with a DX or DX2 microprocessor,
because a math coprocessor is built into the 486DX and 486DX2
chips.
Drives
Your system can support up to four mass storage devices,
including hard disk drives, diskette drives, a tape drive, or a
CD-ROM drive. As your storage needs expand, you can install
additional drives.
4 Introduction