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.
