The ESI32 Uses 30 pin SIMM1, SIMM470, or SIMM16 - Ships with 2Mb stock (two Simm1). 2 memory slots (both are filled with SIMM1s from factory ). Expandable to 32Mb via two SIMM16. Simm8J chips also seem to work but are not “officially” endorsed. SIMMs are installed in matched pairs - You can not mix SIMM types.