**System Information**
Debian Testing. Kernel 3.19.4/4.0.0rc2
2×GPU (GTX 580/750ti)
nvidia version 346.47
2×Multiple display setup 1 monitor for each GPU.
**Blender Version**
2.72.b+dfsg0-3 (debian)
2.73a (official)
2.74 RC2 (official)
**Short description of error**
System/Compute Device/CUDA allows for selecting any or multiple supported devices.
This works fine for rendering and there appears to be no problems as multiple GPU's are utilized for rendering purposes.
However, if Viewport Shading/Render is selected and the CUDA device(s) is not the main display or multiple devices that contains a device that is not the main display device - blender will crash.
I've tested this loading blender to display from either GPU and render to the non-display GPU with no problems unless "Viewport Shading/Render" is selected then blender will freeze (without errors) and at times a system freeze (if display != :0 and I can't kill blender).
Let me know if you require any further information.
Regards.
Joules.
**Exact steps for others to reproduce the error**
Any simple cycles render test.