Re: Titan X on HP Z840

1.  Even the Z620 has two 6-pin supplemental PCIe power cables.... they are plugged into the side of the bottom front black plastic memory fan casing, into "stunt" receptacles that do nothing but hold the plug for you to find.

2.  A HP 6-pin supplemental power cable passes significantly more power than the 75W ATX standard, and there are even HP adapters that pass proper 8-pin cable power via a HP 6-pin cable.  Read here:

http://h30434.www3.hp.com/t5/Business-PCs-Workstations-and-Point-of-Sale-Systems/really-only-1-6pin-power-connector-for-graphics-card/m-p/5664682/highlight/true#M12951