I use Powerstrip.
3DMark2003 seems to be a "graphics card benchmark" more than a gaming system benchmark. I benched with my P4 1.6A and 64mb Radeon 8500 and scored 1109 marks, so I upped the processor to 2.14Ghz and scored 1141 marks. I then put the processor back to 1.6Ghz and overclocked the Radeon from 275/275 to 300/300 and scored 1190 marks. A 34% increase in processor speed got me a 3% increase in score, while a 9% increase in graphics card clock speed got me a 7% increase in score.