There are 3 models of the Raspberry Pi 4 (RPI4) available. They are identical except for the amount of RAM onboard; choose from 1GB of RAM, 2 GB of RAM, or 4GB of RAM. There???s no way of upgrading the RAM once a user has made their purchase. So it???s pretty important to choose the model that best fits your requirements, or you may end up spending more than necessary, or even need to buy extra RPI4???s.