Super Pi
SuperPi is one of the most popular benchmarks with overclockers and tweakers. It has been used in world-record competitions since forever. It is a purely single-threaded CPU test that calculates Pi to a large number of digits—32 million for our testing. Released in 1995, it only supports x86 floating point instructions and thus makes for a good test for single-threaded legacy application performance.
wPrime
While SuperPi focuses on calculating Pi, wPrime tackles another mathematical problem: finding prime numbers. It uses Newton's Method for that. One of the design goals for wPrime was to engineer it so that it can make the best use of all cores and threads available on a processor.