The temptation to use the latest and greatest technology for maximum performance can be powerful, but there are good reasons to opt for a tried-and-tested solution instead. Like NASA did, throwing an original Playstation CPU inside the New Horizons Space probe that is currently beaming pictures of Pluto back to earth.
The MIPS R3000 CPU that was the heart of the Playstation back in the '90s is also the brains behind the New Horizons probe, and that's quite deliberate, with NASA opting for a well-known CPU -- albeit one that they've undoubtedly tweaked a little to keep it safe from the rigours of space travel -- back in 2006. Even then, this chip was really showing its age; the original PlayStation debuted in 1994.
So why go for something old? In a word, reliability. That's the classic ballet between deploying newer and faster gear in the hopes for a productivity boost versus taking on board something a little slower and less efficient in return for a more reliable performance. Sometimes, less is more.