SpawnPoint - Where Game Begins

For the last 4 years I have been buying games that have run slow on my computer even on ultra low settings. Now that I have my new computer, I have been reinstalling my games one-by-one and testing them on full settings. Oblivion, Doom 3, Half Life 2, X3 Reunion, they all get perfect FPS on high settings. However, I tried this with Sim City 4, and it's a slideshow! Even on low settings, it runs slower than on my old compuer. According to some benchmarking software, my video card experiences 0% load while running the game. Oh well, at least I get a bare minimum of 100 FPS in Source games, with an average of 150, and I usually reach the 300 limit. All on the highest settings of course.