"You are right that the processor does feel acient. Our current smarthphones are more powerful. The reasoning for this is three-fold. First of all, the computer was selected about 8 years ago, so we have the latest and greated space certified parts that existed then. Second of all, it was the most rubost and proven space grade processor at that time. Thirdly, in order to make a processor radiation hardened it requires lots of tricks on the silicon that is not conducive to making it fast. Given that, it does not run any GUIs and can just focus on raw programming, and actually gets a lot done."
TIL my smartphone is more powerful than the computer processor in the Mars Curiosity Rover.
My smartphone didn’t land on another planet, though.