Mac Portable 

Physical Memory: Up to 5MB total can be installed using the 
expansion card. The card can hold 1, 2, 3, or 4MB. (Apple 
specifications allow up to 8MB, but 4MB is largest that was 
ever manufactured.) The original Portable uses static RAM, 
and the later, Backlit Portable uses Pseudo–Static RAM. 
The two types are not interchangeable, nor can they be 
used on any other Macintosh. Portable and PowerBook 
RAM are not interchangeable.

Extended Memory: The 68000 CPU in the Mac Portable 
has no Memory Management Unit (which is required to run 
virtual memory). There is currently no upgrade path to 
provide an MMU to the Portable and there will probably 
never be one.

PowerBook 100 

Physical Memory: Up to 8MB can be installed using the 
expansion card. The card can hold 2MB, 4MB, or 6MB. The 
6MB cards are available only from third parties (not Apple). 
PowerBooks use Pseudo–Static Thin Small–Outline 
Packages (or TSOPs). You must buy memory customized 
for a PowerBook 100. Some third parties offer special 
DRAM that works similarly to the TSOP. No extra software is 
required to address the full 8MB.

Extended Memory: The 68000 CPU in the PowerBook 100 
has no Memory Management Unit which is required to run 
virtual memory. There is currently no upgrade path to 
provide an MMU to the PB100 and there will probably never
be one.

PowerBook 140, 145 and 145B 

140, 145 has 2MB soldered on, 145B has 4MB soldered on.

Physical Memory: Up to 8MB can be installed using the 
expansion card. The card can hold 2MB, 4MB, or 6MB. The 
6MB cards are available only from third parties (not Apple). 
PowerBooks use Pseudo–Static Thin Small–Outline 
Packages (or TSOPs). You must buy memory customized 
for a PowerBook 140/145/170. Some third parties offer 
special DRAM that works similarly to the TSOP. No extra 
software is required to address the full 8MB.  32–bit 
addressing is available, but since only 8MB can be installed 
it is not very useful. In most cases, it should be left Off.  The
exception to this is when using extended memory on an 
8MB machine - 32-bit addressing is needed to address 
more than 14MB.

Extended Memory: The 68030 CPU in the PowerBook 140/145/145B has a built–in Memory Management Unit. Therefore, the PB140/145/145B can run RAM Doubler or virtual memory without additional hardware. However, use of virtual memory while on battery power is not recommended because it requires the hard drive to constantly spin, significantly reducing battery life. We recommend RAM Doubler.

PowerBook 150 
Physical Memory: Memory cards of up to 36MB can be 
installed, for a total of 40MB.  RAM is unique  low–power, 
self–refreshing dynamic RAM, and must run 80ns or faster.  

Extended Memory: The 68030 CPU in the PowerBook 150 
has a built–in Memory Management Unit. Therefore, the 
PB150 can run RAM Doubler or virtual memory without 
additional hardware. However, use of virtual memory while 
on battery power is not recommended because it requires 
the hard drive to constantly spin, significantly reducing 
battery life. We recommend RAM Doubler.

PowerBook 160/165 

Physical Memory: 8MB can be installed using Apple’s 4MB 
expansion kit, or up to 14MB can be installed using 
third–party expansion cards. PowerBooks use 
Pseudo–Static Thin Small–Outline Packages (or TSOPs). 
You must buy 85ns or faster RAM for a PowerBook 160/180. 
Some third parties offer special DRAM that works similarly
 to the TSOP. 

Extended Memory: The 68030 CPU in the PowerBook 
160/165 has a built–in Memory Management Unit. 
Therefore, the PB160/165 can run RAM Doubler or virtual 
memory without additional hardware. However, use of 
virtual memory while on battery power is not recommended
 because it requires the hard drive to constantly spin, 
significantly reducing battery life. We recommend RAM 
Doubler.

PowerBook 165c 

Standard Memory: 8MB can be installed using Apple’s 4MB 
expansion kit, or up to 14MB can be installed using 
third–party expansion cards. PowerBooks use 
Pseudo–Static Thin Small–Outline Packages (or TSOPs). 
You must buy 85ns or faster RAM for a PowerBook 165c. 
Some third parties offer special DRAM that works similarly 
to the TSOP. 

Virtual Memory: The 68030 CPU in the PowerBook 165c 
has a built–in Memory Management Unit. Therefore, the 
PB165c can run RAM Doubler or virtual memory without 
additional hardware. However, use of virtual memory while 
on battery power is not recommended because it requires 
the hard drive to constantly spin, significantly reducing
battery life. We recommend RAM Doubler.

PowerBook 170 

Standard Memory: Up to 8MB can be installed using the 
expansion card. 2MB expansion card can be replaced with 
4MB or 6MB cards. The 6MB cards are available only from
 third parties (not Apple). PowerBooks use Pseudo–Static 
Thin Small–Outline Packages (or TSOPs). You must buy 
memory customized for a PowerBook 140/145/170. Third 
parties offer special DRAM that works similarly to the TSOP. 
No extra software is required to address the full 8MB.

Extended Memory: The 68030 CPU in the PowerBook 170 
has a built–in Memory Management Unit. Therefore, the PB 
170 can run RAM Doubler or virtual memory without 
additional hardware. However, use of virtual memory while 
on battery power is not recommended because it requires
the hard drive to constantly spin, significantly reducing battery 
life. We recommend RAM Doubler.

PowerBook 180 and 180C 

Standard Memory: 8MB can be installed using Apple’s 4MB 
expansion kit, or up to 14MB can be installed using 
third–party expansion cards. PowerBooks use 
Pseudo–Static Thin Small–Outline Packages (or TSOPs). 
You must buy 85ns or faster RAM for a PowerBook 180C. 
Some third parties offer special DRAM that works similarly 
to the TSOP.  

Virtual Memory: The 68030 CPU in the PowerBook 
180/180C has a built–in Memory Management Unit. 
Therefore, the PB 180/180C can run RAM Doubler or virtual 
memory without additional hardware. However, use of 
virtual memory while on battery power is not recommended 
because it requires the hard drive to constantly spin, 
significantly reducing battery life. We recommend RAM 
Doubler.

PowerBook 520 and 520c 
Standard Memory: Up to 36 MB may be installed using an
expansion card.  You must buy 70ns or faster RAM for a 
PowerBook 520 or 520c.. 

Virtual Memory: The 68040 CPU in the PowerBook 
520/520c has a built–in Memory Management Unit. 
Therefore, the PB 520/520c can run RAM Doubler or virtual 
memory without additional hardware. However, use of 
virtual memory while on battery power is not recommended 
because it requires the hard drive to constantly spin, 
significantly reducing battery life. We recommend RAM 
Doubler.

PowerBook 540 and 540c 
Standard Memory: Up to 36 MB may be installed using an
expansion card.  You must buy 70ns or faster RAM for a 
PowerBook 540 or 540c.. 

Virtual Memory: The 68040 CPU in the PowerBook 
540/540c has a built–in Memory Management Unit. 
Therefore, the PB 540/540c can run RAM Doubler or virtual 
memory without additional hardware. However, use of 
virtual memory while on battery power is not recommended 
because it requires the hard drive to constantly spin, 
significantly reducing battery life. We recommend RAM 
Doubler.

PowerBook Duo 210 

Physical Memory: Up to 12MB can be installed using 
Apple’s 4MB or 8MB PowerBook Duo expansion kit, or up 
to 24MB can be installed using third–party expansion cards.
RAM is unique for the PowerBook Duo (called low–power, 
self–refreshing dynamic RAM), and must run 80ns or faster. 

Extended Memory: The 68030 CPU in the Duo 210 has a 
built–in Memory Management Unit. Therefore, the PBD 210 
can run RAM Doubler or virtual memory without requiring 
any additional hardware. However, use of virtual memory 
while on battery power is not recommended because it 
requires the hard drive to constantly spin, significantly 
reducing battery life. We recommend RAM Doubler.

PowerBook Duo 230 

Physical Memory: Up to 12MB can be installed using 
Apple’s 4MB or 8MB PowerBook Duo expansion kit, or up 
to 24MB can be installed using third–party expansion cards.
RAM is unique for the PowerBook Duo (called low–power, 
self–refreshing dynamic RAM), and must run 80ns or faster.  

Extended Memory: The 68030 CPU in the Duo 230 has a 
built–in Memory Management Unit. Therefore, the PBD 230 
can run RAM Doubler or virtual memory without additional 
hardware. However, use of virtual memory while on battery 
power is not recommended because it requires the hard 
drive to constantly spin, significantly reducing battery life. 
We recommend RAM Doubler.

PowerBook Duo 250 

Physical Memory: Up to 12MB can be installed using 
Apple’s 4MB or 8MB PowerBook Duo expansion kit, or up 
to 24MB can be installed using third–party expansion cards.
RAM is unique for the PowerBook Duo (called low–power, 
self–refreshing dynamic RAM), and must run 70ns or faster.  

Extended Memory: The 68030 CPU in the Duo 250 has a 
built–in Memory Management Unit. Therefore, the PBD 250 
can run RAM Doubler or virtual memory without additional 
hardware. However, use of virtual memory while on battery 
power is not recommended because it requires the hard 
drive to constantly spin, significantly reducing battery life. 
We recommend RAM Doubler.

PowerBook Duo 270c 

Physical Memory: Up to 12MB can be installed using 
Apple’s 4MB or 8MB PowerBook Duo expansion kit, or up 
to 32MB can be installed using third–party expansion cards. 
RAM is unique for the PowerBook Duo (called low–power, 
self–refreshing dynamic RAM), and must run 70ns or faster.  

Extended Memory: The 68030 CPU in the Duo 270c has a 
built–in Memory Management Unit. Therefore, the PBD 
270c can run RAM Doubler or virtual memory without 
additional hardware. However, use of virtual memory while 
on battery power is not recommended because it requires
 the hard drive to constantly spin, significantly reducing 
battery life. We recommend RAM Doubler.

PowerBook Duo 280 and 280c 

Physical Memory: Up to 12MB can be installed using 
Apple’s 4MB or 8MB PowerBook Duo expansion kit, or up 
to 40MB can be installed using third–party expansion cards. 
RAM is unique for the PowerBook Duo (called low–power, 
self–refreshing dynamic RAM), and must run 70ns or faster.  

Extended Memory: The 68040 CPU in the Duo 280 has a 
built–in Memory Management Unit. Therefore, the PBD 
280 can run RAM Doubler or virtual memory without 
additional hardware. However, use of virtual memory while 
on battery power is not recommended because it requires
 the hard drive to constantly spin, significantly reducing 
battery life. We recommend RAM Doubler.

Macintosh Duo Dock and Duo Dock II

Video RAM: The Macintosh Duo Dock has 512K of 68–pin VRAM soldered on and 1 expansion slot in 1 bank. The standard 512K of VRAM is enough to support 8–bit color on all monitors up to and including the 16" color monitor. This can be expanded up to 1MB, which is enough to support 16–bit color on all monitors up to and including the 16" color monitor. The Duo Dock only supports 100ns 512K VRAM SIMMs.

Macintosh Duo MiniDock

Video RAM: The Macintosh Duo MiniDock has 512K of 68–pin VRAM soldered on. This is enough to support 8–bit color on all monitors up to and including the 16" color monitor.  512K is the maximum amount of VRAM that can be installed in the Duo MiniDock.