It really depends on the size and amount of files you are using in a sidescan mosaic. Mosaics can use a huge amount of data, and 2GB is not a lot of RAM by today's standards. We don't specify a minimum but we have always recommended 8GB (and a 64 bit OS) when creating mosaics because of the extreme data requirements. If you can, upgrading the amount of RAM in your computer will offer you significant performance benefits across the board, and usually for not a lot of money.
