Z6 G4 PSU connector R1

[PupuL]

My Z6 G4 power supply has an unused connector labelled R1. It has similar form factor to the P1 connector, which is currently connected to the motherboard.

What is the intended use of the R1 connector and what does it deliver? Can it be repurposed for a second GPU?

[DGroves]

if you don't have a sec cpu installed i suspect the R1 connector

on the power supply is for the sec cpu when it's installed

if i'm right the R1 connector on the power supply

should have  a 2x5 pin connector

[PupuL]

Yes, 2x5 sounds right. You have a pinout handy?

[SDH]

As usual, agree with DGroves. I believe the R in R1 stands for riser. Power into the riser assembly is higher than for the two different risers used in the Z620 and Z640 workstations. There is a flat black cable in the Z6 G4 workstations that were shipped with the 2nd CPU riser in place, shown here. These generally were not included if the workstation was not shipped with a riser in place:

That video is from HP, HERE. That flat black extension cable can be found on eBay and it is critical to have if you wanted to add a riser to the Z6 G4 workstation. Some added pics from eBay are:

I've never seen a pinout for this extension that goes from its short source at the butt-end of the power supply down to where the Z6 G4 riser can plug into its 2 x 10 plug end. Don't expect to get a pinout from HP. The earlier risers for the Z620 and Z640 did not use this type of a power supply extension cable adapter. Some added info: HP 857711-002 Z6 G4 2nd CPU Riser Power Cable 915746-002 857711-001 L10312-001