Which DDR Is Which? Here Is A Full Guide To RAM.
DDR Ram
Many computer enthusiasts know exactly what they want when they go to configure their new system. They’ve researched and picked out a perfectly matching CPU, motherboard and videocard combination that will meet all their needs. However, when it comes to RAM many users become totally befuddled. They generally know how much RAM they need (1GB is the effective operating minimum these days, 2GB if running Vista or using hungry apps like Photoshop), but they don’t have a clue as to what DDR1, DDR2 or DDR3 means.
It turns out that selecting the proper DDR variant is a very important factor that determines how your overall system will perform, thus every enthusiast/prosumer/gamer should be well-advised to learn the basics.
Double Data Rate DIMM is known as DDR-DIMM, DDR DIMM, or most popularly just plain DDR. Double Data Rate interfaces provide two data transfers per differential clock. The data becomes registered when the CK goes high [the + side], and /CK goes low [the - side]. DDR1 utilizes the JEDEC standard for Double Date Rate [DDR I] SDRAM. Like all DDR RAM it is available as registered or unbuffered. Registered DIMMs are generally known as FB-DIMMs and have their address and control lines buffered in order to reduce signal loading. FB-DIMMs are considerably more expensive than unbuffered DIMMs and are generally reserved for server use. There are very few enthusiast/prosumer/gamers utilizing FB-DIMMs in their rigs. Unbuffered DIMMs don’t feature address lines and control line buffering, so they cost quite a bit less. However, they may be system-loading limited and are thus generally restricted in the number that can be fitted onto one system. You’ll find that most unbuffered DIMMs these days can only be installed on one motherboard to a maximum of 4 x 1GB. Buffered or registered DIMMs don’t have these limitations and server boards can accomodate 8 x 1GB, 16 x 1GB or more. An interesting and largely unknown aspect of unbuffered DDR DIMMs is that they are able to operate one clock cycle faster then FB-DIMMs.… >>> MORE
