Fans constant 3,500 rpm

Hi all I have the new unibody 17 MBP 3.06. The unit doesn't get hot and I love it, but my fans run at a constant 3300-3500 rpm (istat and SMC fan control). The lowest setting on SMC is 100 rpm I wanted it to run around 2000, but when I set it up the fans rev down then 1 second after revving down to the slower speed run right back to 3500 area. Is this normal? I thought SMC was to override the apple settings. Just 2700 rpm's makes a sound difference on my MBP. Any advice would be greatly appreciated. Thanks.