Boy, there are a lot of different types of memory out there!
RAM - Random access memory (RAM) This is the most common computer memory which is used by programs to perform tasks. It is an integrated circuit memory chip which allows information to be stored or accessed in any order and all storage locations are equally accessible.
ROM Read-only memory (ROM) is an integrated circuit programmed with specific data when it is manufactured. This is data stored in a medium that allows it to be accessed but not erased or altered. ROM chips can contain instructions and data.
Cache - pronounced "cash." Small portion of high-speed memory used for temporary storage of frequently used data. Reduces the time it would take to access that data, since it no longer has to be retrieved from the disk. There are memory caches, hardware and software disk caches, page caches and more.
Dynamic RAM (DRAM) - pronounced "dee-ram." A common type of computer memory that uses capacitors and transistors storing electrical charges to represent memory states. These capacitors lose their electrical charge, so they need to be refreshed every millisecond, during which time they cannot be read by the processor.
Static RAM SRAM - pronounced “essram.” Static Random Access Memory (SRAM) is a type of semiconductor memory. Used mostly for Cache Memory, SRAM holds information in memory as long as the power is on. It doesn't have to be constantly refreshed like DRAM. Static RAM is faster than DRAM and is primarily for cache.
Flash memory - Flash memory is used for easy and fast information storage in such devices as digital cameras and home video game consoles. It is used more as a hard drive than as RAM. Flash memory is considered a solid state storage device, meaning there are no moving part.... everything is electronic instead of mechanical.
Virtual memory - Also called disk memory. When all physical memory is in use, a system can simulate more memory by using empty sectors in the hard drive to store additional data.
Video memory VRAM - VideoRAM, also known as multiport dynamic random access memory (MPDRAM), is a type of RAM used specifically for video adapters or 3-D accelerators. Multiport meaning that it can be accessed by two devices simultaneously. This allows the monitor to access the memory for screen updates and allow the graphics processor to provide new data. VRAM must be fast to keep up with the speed at which the screen is scanned.
BIOS (Basic Input / Output System) - pronounced "bye-ose" Basic Input / Output System. The BIOS is built-in software that determines what a computer can do without accessing programs from a disk. On PCs, the BIOS contains all the code required to control the keyboard, display screen, disk drives, serial communications, and a number of miscellaneous functions. The BIOS communicates between the operating system and the computer's hardware.