THe S3000XL uses standard 72 pin SIMM chips (our Q type SIMMs in inventory). 2Mb stock soldered on mother board. Has two SIMMs slots that can hold 4 or 16Mb SIMMs. Simms can be installed in singles. Possible memory configurations are 2Mb, 6Mb, 18Mb, and 32Mb (when you install two 16Mb SIMMs you lose the 2Mb on the mother board). Also you have 2 card slots in the back of the machine that take 8Mb flash ram cards (FMX008) - 2 cards can be installed at the same time for 16Mb of flash ram (basically ROM) samples. Fully blown machine would have 16Mb ROM samples and 32Mb sample RAM.