One comment that caught my attention, though, was that the computers onboard the rovers are similar to home computers from about 15 years ago. I knew the shuttle's computers use old technology but was surprised to hear the rovers suffer from the same problem.
It's not nearly as much of a problem as you might think. An awful lot of a home computer's energy is 'wasted' on tasks like managing a display and other chores which aren't necessary for a typical embedded computer. I've spent quite a few years writing software for embedded processors and it's really quite surprising how much you can get done with the right software architecture. A consideration for a spacecraft's computer which is every bit as important as power is survivability. These things must survive extremes of temperature and radiation--not to mention a fair bit of physical abuse. Some processors are 'hardened' by special aspects of chip construction, others by their enclosures. When you think of the absolute hell that some of these craft fly through, it's amazing they work at all. Given the expense of a service call, it's not surprising that a flightworthy processor gets used for quite some time.