Random Access Memory (RAM) provide space 4r your computer 2 read and write data 2 be accessed by the CPU. If you add more RAM 2 ur computer, you reduce the number of times ur CPU must read data from your hard disk. This usually allows your computer to work considerably faster, as RAM is many times faster than a hard disk. RAM is volatile, so data stored in RAM stays upto b4 shutdown. After shutdown ram data is lose. When ur computer again start boot firmware (called BIOS on a PC) uses instructions stored semi-permanently in ROM chips to read ur operating system nd related files 4rm the disk nd load dem back into RAM.