Installing External Cache

You can install 64KB, 128KB, or 256KB of external cache on your system.

To install 64KB of external cache, use eight SRAM, 28-pin, 8K x 8,20ns DIP chips, and one 8K x 8,201ns tag chip

To install 128KB of external cache, use four SRAM, 28-pin, 32K x 8,20ns DIP chips, and one 8K x 8,20ns tag chip

To install 256KB of external cache, use eight SRAM, 28-pin, 32K x 8,20ns DIP chips, and one 32K x 8,20ns tag chip.

The table below lists the cache SRAM DIP chips that are approved for use in your computer.

Cache SRAM DIP chip types

Manufacturer

Part number

Manufacturer

Part number

 

UMC (8K x 8)

UMC164K-20

samsung (32K x 8)

KM68257BP-15/20

 

Cypress (8K x 8)

CY78165-15

Paradigm (32K x 8)

PDM1256S-20

 

 

 

 

 

 

Toshiba (32K x 8)

TC5532K-20

Micron (32K x 8)

MT502568-20

 

 

 

 

 

 

UMC (32K x 8)

UM61256AK-15/20

NKK (32K x 8)

N341256P-20

 

 

 

 

 

 

Winbond (32K x 8)

W24257AK-15

I Aster (tag)

AA88128AK-20

 

For the cache memory to work properly, you must install chips in the following configuration (each bank contains four cache memory sockets):

Cache memory configurations

Bank 0

Bank1

Tag SRAM

 

U23 - U26

U30 - U33

U34

Total cache

 

 

 

 

8Kx8

8Kx8

8Kx8

64KB

 

 

 

 

32Kx8

-

8Kx8

128KB

 

 

 

 

32Kx8

32Kx8

32Kx8

256KB

 

 

 

 

Installing and Removing options 3-21