Tuesday, 6 January 2015

difference between DDR3 and DDR4

Random-access memory (RAM ) is a form of computer data storage. A random-access memory device allows dataitems to be read and written in roughly the same amount of time regardless of the order in which data items are accessed.[1] In contrast, with other direct-access data storage media such as hard disksCD-RWsDVD-RWs and the older drum memory, the time required to read and write data items varies significantly depending on their physical locations on the recording medium, due to mechanical limitations such as media rotation speeds and arm movement delays.
Today, random-access memory takes the form of integrated circuits. RAM is normally associated with volatile types of memory (such as DRAM memory modules), where stored information is lost if power is removed, although many efforts have been made to develop non-volatile RAM chips.[2] Other types of non-volatile memory exist that allow random access for read operations, but either do not allow write operations or have limitations on them. These include most types of ROM and a type offlash memory called NOR-Flash.

DDR4 Power Savings Features
 DDR4 voltage is 1.2 V (up to 40% savings)
− Lower voltage than DDR3 (1.5 V)
− On-die VREF
− Pseudo-open drain I/Os
 Manages refreshes (up to 20% savings)
− Based on temperature
 New DDR4 low-power auto self-refresh (LPASR) capability
− Changes refresh rate based on temperature
− Only refreshes parts of array that is in use
 Controller must allow fine-granularity refresh based on memory utilization
 Supports data bus inversion
− Limits number of signals transitioning, reducing simultaneous switching
output (SSO) and saving power

Comparison Between Various Latest RAM:



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