Ann: Appendix 4E & Annual Report, page-212

DRAM is basically a chain of logic gates that require a continuous flow of power to retain a state of 1 or 0 in each bit of memory. When that flow of power stops, everything is gone. DRAM is measured in gigabytes, not terabytes, on most systems.

I believe SCM provides a class of storage you don't currently see in systems. Potentially terabytes of database storage can be held and manipulated at near DRAM speeds, but without the power consumption and high cost of using DRAM for the task. It's hard for me to fathom why this is important, but I trust those in the industry who say it is. Retention requirements in this space are less than your thumb drive, hard disk, etc.