8556/57 Cached Processor Upgrade

191-201 Cached Processor Option for Model 8557
SHS04G5106 IBM PS/2 Cached Processor Option HML
EPRM IBM PS/2 Cached Processor Option for Mod. 56/57

rf855657.exe 8556/8557 reference diskette v2.10 -supports SLC2/SLC3 upgrades

8556/57 Diags Disk Ver 2.04 or better supports all 8556/57 386SX / SLC systems, including 8556/57 systems with processor options: 386SLC, 486SLC2, and 486SLC3.

8556/57 Cached Processor Upgrade FRU 92F0078

Note the unpopulated jumper "BYPASS JUMPER".

Not having one in-hand, I see the wires from the OS1 outline, going under the heatsink.

Upgrade Installation


  • IBM 386SLC-20 with Internal memory cache controller and 8KB cache memory
  • Improves processor throughput up to 88% depending on application
  • Installs into a math co-processor 121-pin socket connector
  • Provides a socket for 80387SX 20MHz or equivalent math co-pro.

Content created and/or collected by:
Louis F. Ohland, Peter H. Wendt, David L. Beem, William R. Walsh, Tatsuo Sunagawa, Tomáš Slavotínek, Jim Shorney, Tim N. Clarke, Kevin Bowling, and many others.

Ardent Tool of Capitalism is maintained by Tomáš Slavotínek.
Last update: 08 May 2024 - Changelog | About | Legal & Contact