Reference Guide

Mac Plus 

Physical Memory: Uses 256K and 1MB SIMMs. Up to 4MB
 can be installed using four 1MB SIMMs. Other common 
configurations are 1, 2 and 2.5MB. To add RAM to a Mac 
Plus you need to cut the R8 resistor on the motherboard. If 
you want to run System 7, you should probably install all 
4MB of RAM.  To use more than 4MB of physical RAM you 
need to install a 68030 accelerator and Connectix Compact 
Virtual 3.0. On most accelerators you can then install four 
4MB SIMMs for a total of 16MB of application memory.

Extended Memory: The 68000 CPU in the Mac Plus has no 
Memory Management Unit (which is required to use 
extendedmemory). If you add a 68030 accelerator, this will 
contain a built–in MMU, but System 7 VM will still not work. 
Use Connectix Compact Virtual 3.0 to create 16MB of virtual 
memory on the accelerated Mac Plus. Compact Virtual always uses 24–bit addressing, so 32–bit compatibility is not required. It will work on System 6 or 7.

Mac SE 

Physical Memory: Uses 256K and 1MB SIMMs. Up to 4MB
 can be installed using four 1MB SIMMs. Other common 
configurations are 1, 2 and 2.5MB. To add RAM to an early 
SE you need to cut the R35 resistor on the motherboard. For 
later SE’s you need to move a jumper (2MB) or remove the 
jumper (2.5 or 4MB). On the early SE’s, Bank A is the one 
toward the back (slots 1 and 2). On the later SE’s, Bank A is
the one toward the front (slots 3 and 4). If you want to run 
System 7, you should probably install all 4MB of RAM.

 To use more than 4MB of physical RAM you need to install a 
68030 accelerator and Connectix Compact Virtual 3.0. On 
most accelerators you can then install four 4MB SIMMs to 
have a total of 16MB of application memory.

Extended Memory: The 68000 CPU in the Mac SE has no Memory Management Unit (which is required touse extended memory). If you add a 68030 accelerator, this will contain a built–in MMU, but System 7 VM will still not work. Use Connectix Compact Virtual 3.0 to create 16MB of virtual memory on the accelerated Mac SE. Compact Virtual always uses 24–bit addressing, so 32–bit compatibility is not required. It will work on System 6 or 7.

Mac Classic 

Physical Memory: The socket can be filled with a special 
adapter card. The Apple version of this card comes with 
1MB of RAM and sockets to hold two more standard 256K or 
1MB SIMMs. These last two sockets are a bank; they must 
both be filled or both be empty. The built–in memory is 150ns 
RAM, but added memory must be 120ns or faster. A total of 
4MB can be installed using 1MB SIMMs. To add RAM to a 
Classic you usually need to move a jumper on the adapter 
card, (depending on which manufacturer’s card you use). If 
you want to run System 7, you should probably install all 
4MB of RAM.  To use more than 4MB of physical RAM you 
need to install a 68030 accelerator and Connectix Compact 
Virtual 3.0. On most accelerators you can then install four 
4MB SIMMs to have a total of 16MB of application memory.

Extended Memory: The 68000 CPU in the Classic has no Memory Management Unit (which is required to run virtual memory). If you add a 68030 accelerator, this will contain a built–in MMU, but System 7 VM will still not work. Use Connectix Compact Virtual 3.0 to create 16MB of virtual memory on the accelerated Classic. Compact Virtual always uses 24–bit addressing, so 32–bit compatibility is not required. It will work on System 6 or 7.

Mac Classic II  

Physical Memory: A total of 10MB can be installed using 2 
additional 4MB SIMMs. Surprisingly, the Classic II does not 
support 256K SIMMs.  The Classic II is different from the other
Compact Macs, having ROM software more like the Modular
 Macs. Up to 8MB of memory can be addressed in 24–bit 
mode on the Classic II, while only 4MB can be addressed on
 the Plus, SE, or Classic. The Classic II supports 32–bit 
addressing, though physical RAM is still limited to 10MB.   
8MB or 16MB SIMMs will only be recognized as 4MB SIMMs 
and are not recommended. So, memory configurations are2, 
4, 6, or 10MB.

Extended Memory: The 68030 CPU in the Classic II has a 
built–in Memory Management Unit. Therefore, it can run RAM 
Doubler or virtual memory without requiring any additional 
hardware. In 24–bit mode, the Classic II can address up to 13MB of VM, and in 32–bit mode, it can address up to 1024MB. 

Mac Color Classic 

Physical Memory: The SIMM bank may either be empty, or
 filled with two SIMMs, which must be of the same size. The 
Color Classic does not support 256K or 512K SIMMs. Up to 
8MB of memory can be addressed in 24–bit mode on the 
Classic II, while only 4MB can be addressed on the Plus, SE, 
or Classic. The Classic II supports 32–bit addressing, though 
physical RAM is still limited to 10MB.   8MB or 16MB SIMMs 
will only be recognized as 4MB SIMMs and are not 
recommended. So, memory configurations are2, 4, 6, or 
10MB.

Extended Memory: The 68030 CPU in the Color Classic has 
a built–in Memory Management Unit. Therefore, it can run 
RAM Doubler or virtual memory without additional hardware. 
In 24–bit mode the Color Classic can use up to 14MB of 
Connectix Virtual, or 13MB of System 7 VM. In 32–bit mode it can use up to 1024 MB of virtual memory (or the amount of available hard drive space.) When performance is critical, or hard drive space is limited, we recommend RAM Doubler.

Video RAM: 256K soldered on. One expansion slot is available for a maximum of 512K video RAM.