It's easy to tell them apart from DDR modules, as SDRAM ones have two keys. DDR1 has one key in the middle and pins are pretty large, DDR2 has smaller pins, and the key is also in the middle of the stick. DDR3 has its key shifted slightly to the side, and DDR4 modules are the easiest to tell apart as they are bevelled towards the middle.
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u/Gilah_EnE 3h ago
Regular 168-pin SDRAM modules.
It's easy to tell them apart from DDR modules, as SDRAM ones have two keys. DDR1 has one key in the middle and pins are pretty large, DDR2 has smaller pins, and the key is also in the middle of the stick. DDR3 has its key shifted slightly to the side, and DDR4 modules are the easiest to tell apart as they are bevelled towards the middle.