Partial array self refresh (PASR), automatic temperature compensation self refresh (ATCSR), deep power down (DPD) and other standardized Mobile RAM special low-power functions enable a longer battery operating time.

Powering down or powering up when needed is not a comparison of battery longevity in driving a continuous play condition. It only relates to the chip power consumption at idle. This condition more relates to the burn involved for refresh of a capacitor based RAM. You have to add to that,  the continuous play consumption of a device and that relates to the OS hardware requirements.

 You're either burning a stream or your not.

e.Digital implements RAM(static) at very minimal size that does not require refresh. They can further,  if needed,  implement RAM(static) that has power down ability when not in a full signal state. The reason others do not utilize it,  it's expensive and they would need 10 times the foot print.

doni