1. The type of RAM supported by your motherboard: DDR3 or DDR4.
2. The speed of the RAM: higher speeds (measured in MHz) will provide a performance boost.
3. The voltage of the RAM: this determines its power consumption.
4. The amount of RAM you require: 8GB is a good amount for general computing, while 16GB is recommended for gaming.
5. And lastly, the cost: aim to select RAM with a good balance of price and performance.