If, while it is working, a computer starts to run out of free Ram it will have to dump some of its information to make more working space. This is done by saving parts of the Ram onto the hard disk, using the free space thus gained, and then reloading the original memory from the hard disk. This slows down the computer because hard disks are very slow compared to the Ram. You should therefore make sure that you have at least 8Mb Ram, or 16Mb if you can afford it.
