@MasterChief: How is this external GPU connected to the computer? What model is the GPU? What OS and bitness (e.g., Win7, 64bit) is your computer?

I've never encountered an external GPU, but I would think that to use it for GPU rendering, the bandwidth of the connection would have to be massive.

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5