Picked up a 2009 2x 2.66 quad mac pro and upgraded to 2x 3.33 six cores. Before the upgrade the fans were spinning in an oscillated manner - Up for a few seconds, then down for a few seconds and so on. I didn't do any troubleshooting because I was going to upgrade the cpus anyways. Once swapped, the fans stopped exhibiting this behavior, except for when I open up any program for the first time after startup. They'll speed up for about 7 seconds and then slow down and remain normal until I restart and open up a program again. I've already tried blowing out any dust as well as performing an smc reset. Not sure what else to try. This seems really weird. Never seen this before. Anyone have any suggestions?