Buyers must distinguish between DDR3, DDR4, and DDR5 technologies, as they are not backward compatible. Key metrics include Frequency (MHz), CAS Latency (CL), and Voltage. For server-grade applications, ensure the RAM supports ECC (Error Correction Code) and is Registered (RDIMM), whereas consumer-grade builds require Unbuffered (UDIMM) or SO-DIMM for laptops. Always verify the chip brand (e.g., Samsung, SK Hynix, Micron) as the quality of the DRAM die directly impacts overclocking stability and failure rates.