The original M6709LL/A iMac comes standard with 32 MB of SDRAM, expandable to 128 MB. The /B iMac, the 266 MHz, and the 333 MHz models come standard with 32 MB of SDRAM, expandable up to 256 MB. The microprocessor board has two RAM expansion slots that accommodate standard SO-DIMMs. The expansion slot on the underside of the board is normally occupied by the factory-installed SO-DIMM. The top slot is available for a user-installed SO-DIMM.

SDRAM Configurations
32 MB	The iMac logic boards come standard with 32 MB of SDRAM (one 32 MB SO-DIMM).
Up to 256 MB	M6709LL/A: expandable to 128 MB (use two 64 MB SO-DIMMs). M6709LL/B, 266 and 333 MHz iMacs: expandable to 256 MB (use two 128 MB SO-DIMMs).

Note: SDRAM DIMMs can be installed one at a time, and in any slot as there are no interleaving benefits. If you're using 128 MB SO-DIMMs, make sure they have been qualified for use in the iMac. Important: RAM expansion SO-DIMMs for the iMac must use SDRAM devices. If the user installs an SO-DIMM that uses EDO or SGRAM devices, the computer will beep several times when the user attempts to restart the computer. Video Memory Note: The M6709LL/A iMac comes standard with 2 MB of SGRAM video memory, upgradeable to 6 MB of video. The /B, the 266 MHz, and the 333 MHz iMacs come standard with 6 MB of SGRAM; 2 MB on board and a 4MB module installed in the video memory slot.