This picture shows the Rover of the Mars Pathfinder. It's zooming across the surface of Sol 4 at about one thirtieth of a mile per hour. The solar cells provide only 16.5 watts at Martian noon. They have to power the wheels, the radio to the base station, the instrument package, and a 2 MHz 8 bit microprocessor - an Intel 80C85.
The Pathfinder base station contains rather more compute power. It has an IBM RS6000 - more or less a PowerPC - running at 20 MHz.