1. DDR1 SO-DIMMs: DDR1 (Double Data Rate 1) SO-DIMMs are the oldest type and were used in older notebooks released in the early 2000s. They operate at a lower memory speed compared to newer generations and have a maximum capacity of 2 GB.
2. DDR2 SO-DIMMs: DDR2 SO-DIMMs replaced DDR1 and were commonly found in notebooks released from around 2004 to 2007. They offer higher memory speeds and capacities compared to DDR1, with maximum capacities reaching up to 4 GB.
3. DDR3 SO-DIMMs: DDR3 SO-DIMMs are a significant improvement over DDR2 and became widely adopted in notebooks released from 2007 onwards. They provide even faster memory speeds and higher capacities, with maximum capacities reaching up to 8 GB or even 16 GB.
4. DDR4 SO-DIMMs: DDR4 SO-DIMMs are the latest generation of memory modules used in notebooks. They offer the highest memory speeds and capacities among all SO-DIMM types. DDR4 SO-DIMMs are found in newer notebooks released from around 2014 and onwards, and they can have maximum capacities of up to 32 GB or even 64 GB.