Up to 1.5 MEG on one card in 256Kx1 increments. A fully expanded GS-RAM operates at only 375 ma for extremely low power consumption. With an optional piggyback card, GS-RAM can be expanded even higher than 1.5 MEG, and is fully DMA (direct memory access) compatible.
Diagnostic software was part of the A2 Appleworks Expander 2.52 disks.