PB 300/320 RAM Memory Upgrade

Warning Only authorized service personnel should upgrade the system. Anyone who wants to upgrade the system herself/himself should know about the dangers of ESD (Electro-Static Discharge) and the necessary precautions. Unknowingly zapping the components of the computer will void the warranty.


Specifications

1. When upgrading any one of these systems, use SIMMs that have 9 chips on them rather then the ones with 3 chips.
 
2. There are 2 variations of motherboard for this system, each one with different memory configuration.
 
a. SHADOW BIOS and SHADOW VIDEO take 128k off Extended Memory if either or both enabled.
 
b. No Jumper setting required.
 
c. Recommended SIMM speed is 80 ns.
 

Motherboard A

System with surface mount DRAMs (44256s and 41256s) totaling 1MB, and 4 SIMM sockets.
(Supports 256Kb and 1MB SIMMs only).  
 

Total

Dram

Dram

Simm

Simm

Extended

Memory

Bank 0

Bank 1

Bank 2

Bank 3

Memory
1MB (8)44256 (4)41256 NONE NONE 384
2MB (8)44256 (4)41256 (2)256K X 9 (2)256K X 9 1408
3MB (8)44256 (4)41256 (2) 1MB X 9 NONE 2432
5MB (8)44256 (4)41256 (2) 1MB X 9 (2) 1MB X 9 4480

Motherboard B

System with NO surface mount DRAMs, and 4 SIMM sockets.
(Supports 256Kb, 1MB and 4MB SIMMs).
 

Total

Simm

Simm

Extended

Memory

Bank 0

Bank 1

Memory
1MB (2)256K X 9 (2)256K X 9 384
2MB (2) 1MB X 9 NONE 1408
4MB (2) 1MB X 9 (2) 1MB X 9 3456
8MB (2) 4MB X 9 NONE 7552
16MB (2) 4MB X 9 (2) 4MB X 9 15744