Computer RAM Memory Article taken from the book “MCSE In Three Weeks” by C.V.Conner, MCSE, MCDBA, MS, Ph.D. While the memory of a hard disk drive is primarily used for long-term storage of files and information, RAM memory is used by the computer while it actively processes information. When your computer is running a program, that software program is loaded from the hard disk and stored into the computer's RAM memory upon usage. Whenever you stop running that program, it is then taken from RAM memory and stored back on the hard disk drive. Obviously, having more system memory (RAM) is another important factor in the overall operating performance of your computer. Simply put, having more memory makes your software programs run faster, even in Refurbished Computers Recommendations: 2 GB or higher for all new computers. How Much RAM Memory Is Enough? When you don't have enough RAM memory, your computer must resort to an activity known as "swapping". In this state, your computer will have to use parts of the hard disk drive as an additional source of temporary memory. Since accessing memory on a hard disk drive is slower than accessing it from a stick of RAM, memory swapping results in a slower overall performance from your computer. Typically, if you get a computer with only 128 MB to 256 MB of RAM memory and you use the Windows XP operating system, then your computer will frequently use part of your hard disk drive as memory for swapping. Currently, it is best to get at least 512 MB of RAM, no matter which type you get. If it's too much money for you, then go for 256 MB. If you have at least 512 MB, you should have plenty for Windows XP or whatever new software you want on your machine. Main Types Of RAM Memory There are various types of RAM memory currently in use today. These definitions will help you to identify which types you should use in your computer system: DDR (Double Data Rate): The current standard for RAM memory modules, DDR offers greater bandwidth than the older standard, SDRAM. DDR is only available on more modern motherboards right now and it is best to check your motherboard's compatibility with DDR prior to purchasing it. RDRAM (Rambus DRAM): RDRAM ships only with certain Pentium 4 systems at this time, or some outdated Pentium III systems. RDRAM is not used with the AMD Duron or the AMD AthlonXP processors. RDRAM and DDR are the two current best types of memory modules you can get for both speed and performance, however, RDRAM is much more expensive. SDRAM (synchronous DRAM): The replacement for both DRAM and EDO, SDRAM synchronizes memory access with the CPU clock for faster data transfer. EDO RAM (extended data-out RAM): A faster form of DRAM, EDO RAM has now been replaced by the even faster SDRAM. DRAM (dynamic RAM): This older, "classic" form of RAM has been supplanted by SDRAM and DRAM does not see much active use. Currently DDR RAM is probably the best choice, but if may simply come down to which motherboard you have. In many older Refurbished Computers, you might still see SDRAM, but DDR2 is the most commonly used. Unless you're buying a computer system which has a newer type of motherboard built for DDR RAM, you will probably be stuck using SDRAM.