DDR4 SDRAM DDR4 is the latest JEDEC memory standard. It enables higher levels of performance along with lower power consumption and higher reliability than DDR3. JEDEC began working on the DDR4 specification in 2005, with the final specification published in September 2012. Samsung produced the first prototype DDR4 modules in late 2010 and released the first sample 16GB DDR4 module in July 2012. With support expected to be arriving in processors and chipsets in 2014, DDR4 will eventually succeed DDR3 in becoming the most popular type of memory in new systems. DDR4 modules use a Pseudo Open Drain (POD) interface (previously used in high-performance graphic DRAM) and run on a lower 1.2V voltage (compared to 1..5V for DDR3). This enables DDR4 modules to consume about 40% less power overall than previous DDR3 modules, thus saving energy while also producing less heat. DDR44 also supports write Cyclic Redundancy Check (CRC) to improve system reliability. 284 pin DDR4 modules are 1mm longer and 1mm taller than 240-pin DDR3/DDR2 modules. This was accomplished by making the individual pins only 0.85mm wide, versus the 1mm wide pins used on previous modules. Because of the different size and signalling used, DDR4 modules are both physically and electrically incompatible with previous memory module and socket designs. (see Figure 6.5) DDR4 modules are available in speeds of 1,600MHz (effective) and higher, with speeds of up to 3,200MHz (effective) expected in the future. Just as with DDR, DDR2, and DDR3 the true clock speed is half the effective rate, which is technically expressed in million transfers per second (MTps). Table 6.11 shows the official JEDEC-Approved DDR4 module types and bandwidth specifications. (Taken from Chapter 6:Memory page 344--Of Scott Muellers UPGRADING AND REPAIRING PCs 21st EDITION)
Posted on: Sat, 29 Mar 2014 01:12:36 +0000
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