This is a pretty interesting new software called Octane Render that looks very promising indeed. It provides Maxwell Render quality at Hypershot speeds. Octane works using your video card, and is optimized for the Cuda feature set of Nvidia cards. This is the second program I have used that specifically leverages Cuda, and this apparently produces speed increases of 1000 to 1500% over traditional renders. Wow. So if you are putting together a design PC, you might do well to bet on Nvidia video cards.
Both NextLimit and Bunkspeed are purportedly working on GPU based render programs, while the folks behind fryrender already seem to have a product in pre-release.
I am kicking myself a little because I purchased the minimum level of graphics card that would run Solidworks 2009, because traditionally you get your performance from a killer CPU chip and buckets of RAM.
Currently Octane Render only works with obj files, so that is well and good for most CG software like 3DS Max, Maya etc, but you have to go through extra translation for CAD programs like Solidworks.
Get the demo here
Their January render competition