The development of these standards is a reflection of technological developments meant to boost computing system performance & energy economy. Apart from the variations in generation, DIMM slots can also ap goldbe classified according to their dimensions & number of pins. Typically, DDR3 modules have 240 pins in standard DIMMs, while DDR4 and DDR5 modules have 288 pins. But there are also smaller versions, like the SO-DIMM (Small Outline DIMM), whose smaller size makes them popular in laptops and small systems. While choosing compatible memory modules for their systems, users must be aware of these differences.