RAM is an acronym for Random Access Memory that is also known as volatile memory, because the data it holds is lost when the desktop PC or laptop/notebook computer using it is switched off. Briefly, RAM memory is used by the system to store data in the form of files for processing by a computer's central processing unit (CPU), also known as the processor.
The amount of RAM memory used in modern desktop and laptop computers is expressed in megabytes (MB) and gigabytes(GB). A gigabyte (1GB) is 1024MB. Most desktop and laptop computers that came with Windows XP preinstalled came with 512MB. However, this increased to gigabytes when Windows Vista was released in January 2007. A computer with Windows Vista preinstalled should have a minimum of 2GB or RAM memory to run comfortably, however, 1GB of RAM memory in computers running a 32-bit version of Windows 7 should suffice, because the 32-bit versions of Windows 7 can run on a comparatively low-spec netbook computer, most of which currently only have 1GB of memory (January 2010).
32-bit versions of Windows cannot use more than about 3.5GB of memory; 64-bit versions of Windows can support far more memory than most home users require. However, up to 4GB of memory, the 64-bit versions require twice as much memory as the 32-bit versions, so the minimum a 64-bit version should have is 2GB for Windows 7 and 4GB for Windows Vista. Most computers in use currently use a 32-bit version of Windows.
Memory Limits: Windows 7: Version | Limit in 32-bit Windows | Limit in 64-bit Windows | Windows 7 Starter | 2.0GB | 2.0GB | Windows 7 Home Basic | 4.0GB | 8.0GB | Windows 7 Home Premium | 4.0GB | 16.0GB | Windows 7 Professional | 4.0GB | 192.0GB | Windows 7 Enterprise | 4.0GB | 192.0GB | Windows 7 Ultimate | 4.0GB | 192.0GB |
ROM
* ROM: A regular ROM is constructed from hard-wired logic, encoded in the silicon itself, much the way that a processor is. It is designed to perform a specific function