The original psp memory cards were approximately the thickness and size of a chewing gum stick. It was made available in sizes ranging from 4 megabytes to 128 megabytes. This traditional card is no longer made, but since then Sony has released an array of new cards designed for different PSP consoles.

Because of complaints about the original Memory stick size limitations, Sony created the Select series. This series had two partitions of 128MB that the user could rotate between using a physical switch on the top of the card. The solution was very unpopular, but it did provide users with more memory capacity.

The PRO card was introduced as a joint project between SanDisk and Sony to solve the space problem. Most PSPs that used the original cards could support the PRO sticks since both of them had the same form factors. The models that were not compatible could usually be upgraded via a software update. The Pro cards had a slightly higher speed for transfer and a capacity of 32 gigabytes, although they were only sold in 4GB options. The PRO series is still available, and is often sold in newer PSPs that support high speed mode, making game, video, and music streaming much faster. All PRO memory cards that are larger than 1GB have this technology, but they are also backwards compatible so they can work with devices that do not have the High Speed mode. These cards are very expensive compared to normal flash memory cards of the same size, but they are required in order to play games on your PSP.

Most PSP gaming consoles have memory built into the device, but buying a card is a way to expand your space and get new games. A 16GB card is large enough to hold all the new games, with extra space to fit music and videos.