Dual / external PSU?

[g1tigi]

I have an HP Z640 workstation that has just two 6-pin cables for graphics cards (ugh). I'm looking to put in a GPU that requires a 6 and an 8-pin cable.

How straightforward would it be to just power the GPU from another power supply?

Things that won't work
1) plugging the two 6-pin cables into the GPU--theoretically the last two pins on the 8-pin connector are grounds; but the computer won't boot (error: "please attach pcie power cable")
2) swapping out the psu won't work because HP has some proprietary/custom connectors to the mobo.

thoughts?

 

[Tsumi]

A 6 pin to 8 pin adapter will make it work, as one of those 2 grounds is actually a sense pin, which needs to be connected for it to properly work.

What GPU do you want to put in, and what are the specs of the PSU?

 

[g1tigi]

Ah, good to know that the adapter will work, and also why plugging the 6-pin in directly did not work.

The GPU is a GTX titan (original), and the PSU, per HP specs, is a "925W, 90% Efficient Power Supply". Unfortunately there are no specifics beyond this. But seeing that this workstation can support, e.g. a Quadro K6000, I highly doubt that there will be any issues with these two 6-pin connectors being able to supply enough juice.

There are two E5-2680 CPUs in the machine already, but I think there should still be adequate headroom.