You don’t have to worry about losing any personal information when you perform a memory upgrade because your DRAM memory does not store that data.
Unlike the type of memory you find in a hard disk drive or solid state drive (SSD), the memory in DRAM modules is called “volatile” memory. This means that when a system is turned off, all data is erased. Things like your personal documents, programs, operating system, and personal settings are all stored on your local drive. When a computer is shut off, your storage drive will keep your data stored for access the next time you turn your system on. When you first turn your computer on, it actually has to read all the files and programs from your storage drive, then load them onto your DRAM memory. This is why booting up a computer can often take a very long time if you don't have enough DRAM.