Unlike its PC counterpart, RAM works in a different manner in smartphones. The apps we use are first loaded to the RAM and then executed. When these applications are no longer in use, they get shifted to the background so that the free RAM is now available for faster retrieval. The more the RAM, definitely faster will be the performance but lesser will be the battery life.
The original low-power DDR (called LPDDR1) has a reduced supplied voltage of 1.8V. The chips are smaller thereby using less board space than their non-mobile equivalents. Samsung and Micron are two of the main providers of this technology, which is used in tablet computing devices such as the Apple iPad, Samsung Galaxy Tab and Motorola Droid X. This type of RAM is now outdated.
LPDDR2 is designed to extend the life of a seven-hour battery by about 45 minutes during typical mobile operation.For standby power, the savings are even more dramatic.For example, LPDDR2 can add up to three days of standby battery life for a smartphone which is a 23 percent improvement over LPDDR1, increasing from 12.5 to 15.4 days. This type is also outdated.
In comparison to LPDDR2, LPDDR3 offers a higher data rate, greater bandwidth and power efficiency, and higher memory density. LPDDR3 achieves a data rate of 1600 MT/s and utilizes many new technologies like write-leveling and command/address training. Products using LPDDR3 include the iPhone 5S, Nexus 10 and Samsung Galaxy S4 (GT-I9500).
LPDDR4 is capable of transmitting data at 3,200 Mbit/s, thus providing 50 percent higher performance than the fastest LPDDR3 and consuming around 40 percent less energy at 1.1 volts. The next-generation LPDDR4 DRAM will contribute significantly to faster growth of the global mobile DRAM market, which will soon comprise the largest share of the entire DRAM market. It enabling end users to have faster, more responsive applications, more advanced features, and higher resolution displays while maximizing battery life. DDR4 is currently used in Asus Zenfone 2, Xiaomi Mi Note Pro, Lenovo K80, Samsung Galaxy S6, Samsung Galaxy Note 4 and OnePlus 2.