Re:Clearing things up a bit (Score 1)

Existing software will continue to run on the individual processor cores. Something that they've done for a long period of time. Old software may not get any faster due to a change in focus toward parallelism vs. increased core speed, but it's not going to suddenly come to a screeching halt any more than my DOS programs from 15 years ago are.

This somewhat depends on what architects do. If they add another level of cache to a processor then that increases the penalty of a cache miss which could lead to a decrease in performance... just a thought.

A lot depends on what hardware architects and mass-market compiler developers start doing when they get beyond having just 4 or so cores on a processor. Performance of legacy code remaining fixed in terms of wall-clock time to solution forever definitely depends on a number of things.