Determine the memory interface. The memory used now is DDR3, and almost all motherboards on sale are DDR3 memory. If you are an old machine and use DDR2 memory, you must buy DDR2 memory. Because DDR-DDR 3 are incompatible with each other.

Determine the memory capacity. Determine the size of the memory stick according to the computer configuration. At present, most computers are equipped with 4G memory. If equipped with a CPU above i5 level, the memory is more than 8G.

Determine the frequency and whether overclocking and dual channel (multi-channel) are needed. The memory frequency of DDR3 is now as high as 2400. If your CPU is a powerful overclocking CPU, such as i7 4930K, you need to be equipped with multi-channel high-frequency memory. In addition, overclocking requires memory. Kingston high-end hacker series and pirate ship are good choices.

Determine the brand of memory. If the requirements are not high, choose the general Kingston, Wei Gang, Qi Zhi, etc. If overclocking is needed, you can choose brands such as pirate ships.

Consider the overall budget. Unlike other accessories, you can add memory at any time (of course, there is still enough memory for the computer to run). If the overall budget is limited, you can consider spending money on accessories such as CPU or graphics card to improve performance. Add more memory chips when you have more money.

Consider compatibility. Try to use the same brand and same frequency memory (different frequencies can be mixed, and high frequencies will be down-converted). If you are upgrading the memory of an old computer, try to use the same brand.