ive got the true control 550 also, and notice fluctuations on my rig listed below and the chiller uses its own power source.
My new ufo case comes in tommorrow, and i bought a fanless 350 psu to power everything but the cpu, mobo and 6800 ultra which ill keep on the true control. Im hopeing that the fluctuations will go now that i will take alot of load off the true control since it was powering 3 scsi drives, fans, 2 opticals, floppy, cpu, mobo, vid card, and im adding 2 sata drives so all that 12v juice will come from the new psu.