Most computers will benefit from a memory upgrade. If the computer has the correct amount of memory it will be able to run the required programs and services providing you the experience you expect. Computers will significantly slow down when running a greater number of programmes with a limited amount of memory. 

RAM is a form of computer memory that can be read written extremely fast and the computer uses this to keep track of all the information it requires to run efficiently. 

When the computer runs out of free system memory it will start to use the internal hard drive for working storage and this is achieved at the expense of speed. This is why a RAM upgrade will often make a huge difference in computer usability