I just replaced the power supply on my z545 - again - and wanted to verify what P7 attaches to. I ask this because on the original power supply it was not attached to anything, so I left it dangling when I replaced it. It ran fine for a couple of years, so there is probably not a problem, but I thought that I should check with others.
Jim
P1 - 24-pin, motherboard
P2 - SATA
P3 - 4-pin, media drive bay
P4 - 4-pin, DVD
P5 - 4-pin, motherboard
P6 - 7-pin, daugherboard (front panel, IR, etc.)
P7 - 3-pin, NOTHING