The Intel LINPACK distribution contains, besides the library, a sample benchmarking application using it, and that happens to be a very intense and "real" workload (solving systems of equations, i.e. scientific computation.) There's plenty of posts on various PC enthusiasists forums about how to run it correctly. (And plenty arguing that it's irrelevant, mostly because their insane overclock seems fine but instantly fails this test. There's a good reason most doing "real" scientific computing don't overclock; a lot of CPUs just barely pass this absolutely realistic test with stock speeds and voltages.)