DDR3 Memory

In computing, DDR3 memory stands for Double Data Rate type three memory. It is a type of memory often used in computers and other electronic devices. It has been in use since 2007. DDR3 memory is neither forward nor backward compatible with any earlier type of random access memory due to different signalling voltages, timings, and other factors. DDR3 is a DRAM interface specification. The actual DRAM arrays that store the data are similar to earlier types, with similar performance.

The computer memory is a temporary storage device. It holds the data and instructions that the CPU needs. Before a program can be run, the program is loaded from some storage devices into the memory. This allows the CPU direct access to the program. Memory is a necessity for any computer.

Computer memory is extremely important to computer operation. Computer memory can be built right into a system board, but it is more typically attached to the system board in the form of a chip or module. Inside these chips are microscopic digital switches which are used to represent binary data.

The primary benefit of DDR3 memory over its immediate predecessor, DDR2 memory, is its ability to transfer data at twice the, enabling higher bandwidth or peak data rates. Compared to DDR2 memory, DDR3 memory uses 30% less power. This reduction comes from the difference in supply voltages: 1.8V or 2.5V for DDR2 and 1.5V for DDR3.

The main benefit of DDR3 comes from the higher bandwidth made possible by its prefetch buffer, which is 8-burst-deep. In contrast, the prefetch buffer of DDR2 is 4-burst-deep, and the prefetch buffer of DDR is 2-burst-deep.DDR3 prototypes were announced in early 2005. Products in the form of motherboards appeared on the market in June 2007 based on Intel's P35 Bearlake chipset with DIMMs at bandwidths up to DDR3-1600. The Intel Core i7, released in November 2008, connects directly to memory rather than through a chipset. The Core i7 supports only DDR3. AMD's first socket AM3 Phenom II X4 processors, released in February 2009, were their first to support DDR3.

Memory used in desktops is known as DIMM’s and those for laptops are known as SODIMM Memory. DDR3 DIMMs have 240 pins and are electrically incompatible with DDR2. The two are prevented from being accidentally interchanged by different key notch positions on the DIMMs. DDR3 SO-DIMMs have 204 pins

While the typical latencies for a JEDEC DDR2 device were 5-5-5-15, some standard latencies for JEDEC DDR3 devices include 7-7-7-20 for DDR3-1066 and 8-8-8-24 for DDR3-1333.DDR3 latencies are numerically higher because the I/O bus clock cycles by which they are measured are shorter; the actual time interval is similar to DDR2 latencies (around 10 ns). There is some improvement because DDR3 generally uses more recent manufacturing processes, but this is not directly caused by the change to DDR3.

JEDEC's planned successor to DDR3 is DDR4, whose standard is currently in development. The primary benefits of DDR4 compared to DDR3 include a higher range of clock frequencies and data transfer rates and significantly lower voltage.