Editing Magnetoresistive RAM (section)

===Power consumption===
Since the capacitors used in DRAM lose their charge over time, memory assemblies that use DRAM must [[memory refresh|''refresh'']] all the cells in their chips several times a second, reading each one and re-writing its contents. As DRAM cells decrease in size it is necessary to refresh the cells more often, resulting in greater power consumption.

In contrast, MRAM never requires a refresh. This means that not only does it retain its memory with the power turned off but also there is no constant power-draw. While the read process in theory requires more power than the same process in a DRAM, in practice the difference appears to be very close to zero. However, the write process requires more power to overcome the existing field stored in the junction, varying from three to eight times the power required during reading.<ref>{{cite web |first1=W.J. |last1=Gallagher |first2=S.S.P. |last2=Parkin |url=http://www.research.ibm.com/journal/rd/501/gallagher.html |title=Development of the magnetic tunnel junction MRAM at IBM: From first junctions to a 16-Mb MRAM demonstrator chip |publisher=IBM |date=24 January 2006}}</ref><ref>{{cite web |first=Rajagopalan |last=Desikan |display-authors=etal |url=http://www.research.ibm.com/people/l/lefurgy/Publications/mram-tr2002-47.pdf |title=On-chip MRAM as a High-Bandwidth, Low-Latency Replacement for DRAM Physical Memories |publisher=Department of Computer Sciences, University of Texas at Austin |date=27 September 2002}}</ref> Although the exact amount of power savings depends on the nature of the work&nbsp;— more frequent writing will require more power – in general MRAM proponents expect much [[low-power electronics|lower power consumption]] (up to 99% less) compared to DRAM. STT-based MRAMs eliminate the difference between reading and writing, further reducing power requirements.

It is also worth comparing MRAM with another common memory system&nbsp;— [[Flash memory|flash RAM]]. Like MRAM, flash does not lose its memory when power is removed, which makes it very common in applications requiring persistent storage. When used for reading, flash and MRAM are very similar in power requirements. However, flash is re-written using a large pulse of voltage (about 10 V) that is stored up over time in a [[charge pump]], which is both power-hungry and time-consuming. In addition, the current pulse physically degrades the flash cells, which means flash can only be written to some finite number of times before it must be replaced.

In contrast, MRAM requires only slightly more power to write than read, and no change in the voltage, eliminating the need for a charge pump. This leads to much faster operation, lower power consumption, and an indefinitely long lifetime.