Ariya pointed me again to two pages where SpeedCrunch is a player.
According to the article Top 10 Kubuntu Applications Part 1, SpeedCrunch also fills the gap where CALC.EXE fails to put processing power to work. SpeedCrunch’s view is more informative and input options are more diverse. It provides a running history of the calculations and provides user defined variables.
Edit: A new and dedicated review has been added by the same author.
On yet another article in Spanish, SpeedCrunch: Scientific calculator for PC, you even get a very cute screenshot. Sorry non-latin language folks, but I'm not going to post the translation of the article as I did last time (I translated the title, so no complaining :).