Third GPU as a drawing device

Hi all,

Currently I have a rig of the following setup:

intel 3930K
2 GTX 660 Ti 3Gb (connected with SLI bridge, but default off)
800 Watt PSU
16 Gb 1600 Mhz memory,

I use a dual screen setup ( A HD screen and a small 4:3 screen). On one I do the modeling and compositing, the other I use for the realtime render of my scene. I was considering of buying a cheap card (GT 640 for example) to use as a drawing device, and take the load of my GTX 660 ti’s.

I got the third graphics card installed and ready to go, but I ran into a problem.
My system supports 3 PCi express cards. My setup is as follows:
1st slot: GTX 660 Ti
2nd slot: GT 640
3rd slot: GTX 660 Ti

The reason I set it up this way is because of airflow. Now my problem:
When I want to select the gpu for Cuda in cycles I get these options:

  • GT 640
  • GTX 660 ti (first one)
  • GTX 660 ti (second one)
  • GT 640 + GTX 660 ti (2X )

So I’m missing the one option I’m looking for namely:

  • GTX 660 Ti (2X)

Is it possible to select just my performance cards and leave my drawing card alone? I’m currently using Blender 2.66

Thanks in advance