Re: HP Z620 > 2 questions regarding 6pin >8pin

The HP "6-pin" PCIe supplemental power cables are not to the ATX standard of 75W each.... they provide more, and that has been posted about in this forum.  The wattage info for those two cables should be on the side of your power supply and in your technical and service manual.

Here is some good reading on the issue:  LINK

http://h30434.www3.hp.com/t5/Business-PCs-Workstations-and-Point-of-Sale-Systems/Nvidia-Quadro-Do-I-plug-in-power-adaptor-into-6-pin-or-8-pin/td-p/5084952

I believe a purchase of a high power video card from HP may have the correct adapter included, but maybe that only happens if you buy it as an option during the original purchase of the build-to-order workstations.

Here is more direct from nVidia:  LINK

http://www.nvidia.com/content/quadro/pdf/quadro-power-guidelines.pdf