Yup SQ for Super Quiet. Yup, the older PSU is loud as hell and a aircraft turbine pretty much. It's nice and quiet in my closest right now. The loudest thing now is the 3x 80mm Delta's in the chassisI believe the 'SQ' at the end of the product name stands for Super Quiet, and those PSUs are supposed to be so in comparison to the usual 'aircraft engine' sounding PSUs. I think you are right on getting it as that is exactly what you want for a homelab.