Comment by modeless

If the battery is so small that it can't last 2 years of normal wear without becoming "horrible", the design is bad. Papering over the bad design by making the phone run at less than 60% of rated speed, on purpose, is even worse. Battery wear is expected, but it is not reasonable to expect that the CPU will be affected too, and this has never been disclosed AFAIK. Also, replacing a non-user-replaceable battery is not a "simple" solution.