There are 23 different models of Sony VAIO PCG GR Series laptops. The compact computers come with memory pre-installed, ranging from 128 MB to 512 MB. The removable memory may be taken out and replaced with a larger chip, if desired. The lower-end models can be upgraded to 512 MB, while the newest, highest model may be upgraded to 1 GB. The computers have 2 memory expansion sockets, making it easy to insert new memory chips to increase your computer's speed and performance.