RE:how to make cpu fan always run at max speed
1) Get a 3-pin to 4-pin adapter.
2) Plug the fan into the 3-pin side.
3) Plug the 4-pin side into one of the regular 12v HD/CD-ROM 4-pin power plugs.
*If your power supply comes with 4-pin "Fan Only" plugs, don't use them. They are also sensor controlled. But the 4-pin plugs for the IDE devices are a full 12v and that should work fine.
I had the same dilemma trying to keep my coolermaster LED fans lit without pulsating (they pulsate when fan speeds are less than 100% throttle). The only way to do that was to keep them at full blast constantly, so this was the workaround that worked for me.