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    Great answer! You actually answered the why of it and in an easy to understand way no less.
    – Synetech
    Commented Aug 30, 2013 at 16:12
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    The accepted answer doesn't actually answer the question, whereas this one does.
    – Mark Adler
    Commented Aug 31, 2013 at 17:01
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    You probably avoid mentioning this because it's too "deep down in physics", but I'd like to say that the barrier is less about energy than entropy. SRAM has even smaller capacitors than DRAM and yet doesn't leak, because it uses field-effect transistors instead of resistors – which, vaguely speaking, bypass interference from thermal noise via an externally supplied voltage threshold. Only a few die shrinks into the future will we reach another type on interference – quantum tunnelling – where an actual energy barrier will be the only way to preserve classical information.
    – leftaroundabout
    Commented Sep 2, 2013 at 21:44
  • @leftaroundabout: SRAM doesn't have capacitors at all, except parasitic and perhaps some research designs.
    – MSalters
    Commented Sep 3, 2013 at 6:50
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    @leftaroundabout: Neither SRAM nor DRAM can store a bit for a longer period of time without some form of refreshing that bit (turning a 0.2 back into a crisp 0 bit). SRAM just does that continuously whereas DRAM does it in a rewrite cycle.
    – MSalters
    Commented Sep 3, 2013 at 7:12