The future calculus of memory management

Check into the DoE exascale studies. Moving data from RAM into the processor eats more power, and an absurd amount if it involves an off-board network. Keeping the RAM on will decrease in power drastically soon (phase-change memory with a relatively small cache), but fetching the data error-free? Painful. The voltage gaps have to keep shrinking.

This doesn't necessarily change your VM/oversubscription scenario, but it's crucial at massive scale.