can you post a sample?

Raytrace bounce of 10-11 is way to high(in my opinion) unless you have a specific need. I use 3 or 4 which seems fine for most things.

Poser 7 and earlier do not use the GPU for rendering, just to diaply the image and the preview. If your gpu were failing I would expect defects on other screens , not just poser. 

 

how many threads are you using to render, in your general settings ?