What a perfect analogy! Next time I'm having this discussion with people, I'll have to remember this.

Correct

Example: https://www.cpubenchmark.net/cpu_lookup.php?cpu=Intel+Pentiu...

Other examples: http://www.tomshardware.com/reviews/intel,264-18.html

Except that the absolute pinnacle of motorsport go as high as they can because it is what produces the most power.

Not that this matter for normal cars.

Sure, some sports car engines turn at over 9,000 RPM, but a car stuck in 1st gear on 9 inch wide street tires is not going to go faster than the same car in 5th with 11.5 inch wide racing tires. Even at the pinnacle of motorsport RPM is a poor determinant of speed, it takes a whole system.

That is true, but at least for engines, it's a fairly safe bet, that if the engines goes beyond 12k rpm, it's build for speed.

That said, I suppose this differs depending on wether or not you think of the gearbox as a part of the engine (CPU) or not.

My analogy was comparing the CPU to a car, so I do consider the gearbox. An engine, no matter how many RPMs it can turn, is pretty useless without the vehicle.

The redline is almost never the point of peak horsepower. This is primarily driven by the fact that the valves can't close/open fast enough at these speeds. Its much worse on domestic vehicles that have to care about fuel efficiency (and so can't use stiffer springs) but the effect is still visible even in race cars.

In F1 the previous generation engines was limited to 18k rpm by the regulations. They could go higher, and since they always went up to the 18k, it's safe to say it provided the most power, otherwise they would have shifted before.