Windows 7 Computer not using correct GPU for rendering

I've posted this across a few forums, hoping one might shed some light on the issue.

I have a HPZ840 workstation running Windows 7 with two GPUs installed.

- Quadro 4000 - for Display
- Nvidia Titan X - for rendering
- There's no onboard graphics

The issue is, the computer will only use the GPU that has connections going to it.

If I have a DisplayPort and DVI cable going into the Quadro, the system will render with the Quadro, the Nvidia card isn't utilised at all.

The latest drivers are installed and I tried setting a primary GPU in the BIOS but it defaults to whatever card has connections running to it.


**Here are some heaven benchmark results.**

This is with the DVI and Display port cables attached to the Titan X:
[1]: Link Removed

This is with the DVI and DisplayPort cables attached to the Quadro:
[2]: https://i.stack.imgur.com/V9ZxF.png

Two very noticeable differences.

When in Nvidia Control Panel, it doesn't give me the option to select a GPU to use:
[4]: https://i.stack.imgur.com/NmVNq.png

But Windows notices the cards in Device Manager.

Has anyone experienced anything like this before?

My end goal is to have the Quadro 4000 card only used for display, and the intense rendering tasks to be picked up by the Titan X card.

Is there a certain way I need to setup the cards or a setting I need to change?

If there is any additional information required let me know and I will provide it.

Thanks