Epson 386/25 - Manual (Page 125)

Installing Memory Modules
There are 16 SIMM sockets on the main system board organized
in four banks consisting of four sockets each. Each socket can
contain one memory module.
You must fill the sockets in any bank you use. Since each bank
has four sockets, you must install four SIMMs to fill up the bank.
The following table shows all the possible SIMM configurations
for the Equity 386/25 PLUS. Do not install SIMMs in any other
configuration. Keep in mind that eight 256KB SIMMs (2MB)
are already installed in banks 0 and 1.
SIMM configurations for the Equity 386/25 PLUS
Installing and Removing Options 5-17