Random access memory (RAM) is physical memory that holds the applications, documents and procedures on a computer. Virtual memory is a storage area that holds the files on your hard drive for retrieval when a computer runs out of RAM.
Physical memory are the RAM chips purchased and placed in a slot on the computer motherboard. The RAM is the first memory used when the computer requires memory usage, such as for loading an application or opening a document.
Virtual memory is stored on the hard drive. Virtual memory is used when the RAM is filled. Virtual memory is slower than physical memory, so it can decrease the performance of applications.
Physical memory allocates information in a "first in, last out" process. The information is placed on the stack. Virtual memory uses a process called paging. These pages are laid across the hard drive in fixed sizes.
Physical memory is limited to the size of the RAM chips installed in the computer. Virtual memory is limited by the size of the hard drive, so virtual memory has the capability for more storage.
Users can add more RAM to a computer to increase performance of a computer that uses virtual memory too often. Virtual memory settings can be controlled through the operating system.