Unless you have the ASD (Apple Service Diagnostic) disk to calibrate the fans, I would not recommend removing the processors. When my identical machine started doing this the video card was failing. First thing I would do is to pull the AGP card, clean the contacts and the card fan, if yours has one, and re-seat it. I would also take it outside and pull the lower fans and blow the whole thing out with compressed air. These babies move a lot of air to keep them cool and will build up a lot of dirt. Then also re-seat the RAM. This machine was not intended to be worked on by non-professionals and requires special programs provided only to Authorized Service providers to work on it. If the processors are pulled without the calibration software the fans will race at full speed.
First we need to know what machine this is. Is it an iMac G5 a Power Macintosh G5, a MacPro
power mac g5 - 2.0 processor - 450 or 600 watt power supply