When sourcing laptop RAM, the most critical factor is compatibility with the motherboard chipset and CPU. You must verify the Generation (DDR3, DDR4, or DDR5), as they are not backward compatible due to different pin counts and notch positions. Additionally, check the Form Factor (SO-DIMM), which is the standard for laptops, and the Maximum Supported Capacity (e.g., 16GB, 32GB, or 64GB) per slot. Matching the Frequency (MHz) and CAS Latency (CL) to the laptop's existing specifications is essential to ensure system stability and prevent performance bottlenecks.