IQ is merely a
human benchmark, of
processing ability, and as such is deeply flawed. Benchmarks are,
by definition, attempts to put a
single number on a multi-faceted object.
Two computers are compared with benchmarking software. One has a clockspeed well in excess of the other, while the other has a lot of dedicated hardware such as 3D graphics cards, floating point maths units, and Brownian Motion generators. If they are tested in terms of integer maths, the high-clockspeed one will win. If they test it with a Quake III timedemo the second will win. Which is better? It's a case of horses for courses.
The same applies to people. OK, I may be brighter than you. However, I have difficulty talking to people, get very emotional, and can't concentrate on the job in hand. Who is better in a job? Depends on the job.