Ok guys.. I have had two people in the last two days report heating problems when using this setup. I went out today and pulled a P4 and a 1000mA buckpuck off the shelf mounted it to a copper heat sink and gave it 6v. I let it on for over a minute and the heat sink was hardly warm.

Who else is using a similar setup and have you noticed any issues? I am not sure if I want to blame the P4 or the buck puck.