A phase-change memory (PCM) includes a matrix of storage cells, including at least a first group with at least one cell. Each cell includes a phase change material having at least a first resistance value and a second resistance value, such that the first group can have an identical message encoded therein in at least a first way and a second way. The memory also includes a controller configured to encode the identical message in the at least first group the first or second way, based on which way causes the least amount of writing cost, given current levels of the group. Another embodiment of memory includes a matrix of storage cells, including at least a first group with at least one cell. Each of the storage cells has at least two levels, such that each of the storage cells can have an identical message encoded therein in at least a first way and a second way (the cells can be PCM or another technology). Each one of the storage cells is arbitrarily individually changeable among the at least two levels, and each of the cells is cost-asymmetric. A controller encodes the identical message in the at least first group using the first way or the second way, based on which way incurs a least cost when writing the message into the at least one cell of the at least first group, given current levels of the at least first group.