You should use 72-pin Fast Page or EDO SIMMS with a speed rating of 70 ns (nanoseconds) or faster. They can be either parity or non-parity (if parity is present it will be ignored), and should have gold leads. The MPC2000XL supports 16 MB and 32 MB SIMMS, however we recommend using 2 x 16 MB SIMMS because the manufacturing specifications of 32 MB SIMMS have changed slightly since the introduction of the MPC2000XL and we have discoved that not all 32 MB SIMMS will work.