486SLC2 CPU Upgrade
192-145  IBM 486SLC2 Processor Upgrade 85xx 
slc_util.exe  8555-SLC2 processor upgrade utility dsk (720K image!)
FRU 10G7103 PN 32G3672 (EMEA)  PN 2609582-2620 (USA) 

IBM 486SLC2 Processor Upgrade
This Processor update can be installed on one of the following computers. 
8556 SX, 8556 SLC, 8557 SX, 8557 SLC or 8557 SLC 

      Remove any installed Math Copro (and also any math-Copro empty socket) Install the plastic guide and plastic insert on the system board. 
      Insert any removed Math Copro into 486SLC2 Processor Upgrade board in U1. 
      Install the Upgrade board until the pins are fully-seated, and the edge-snaps click into place. 

486SLC2 Upgrade Board

U1 Socket for PLCC 387SX 
U3 Reverse of mounting pins 
U8 486SLC2 CPU 

o   IBM 486SLC2 microprocessor (40MHz internal/20MHz external) 
o   486SX-compatible Instruction Set 
o   Internal memory cache controller and integrated 16KB cache memory 
o   Improves cpu throughput up to 271% for 386SX-20, 99% for 386SLC-20 systems. Throughput is up to 53% better than for 486SX-20 based systems and up to 20% greater than 486SX-25 based systems.
o   16-byte wide cache line size 
o   Enhances performance, particularly computer-intensive applications 
o   Allows upgrade of Model 56 SX / SLC and Model 57 SX / SLC and M57 SLC systems 
o   Installs into a Math Co-Processor socket connector 
o   Provides a socket for 80387SX 20MHz, or equivalent Math Co-Pro 
o   16MB real memory addressability 
o   64TB (TB = terabytes) virtual memory addressability 

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