The oft delayed Caustic Series 2 raytracing cards are finally available for Pre-order. I've been beta testing a card for the last 6 months and found it incredibly useful. Software support is currently limited to Maya, Rhino and soon Max but if you use mental ray I would recommend checking out the beta/demo to see what it's capable of. And hopefully next year with production cards in the wild software support will pick up too.
The big selling point for me is scene size and shader complexity. The r2500 can hold 120M unique polygons and it uses your system memory for the shaders and maps which means for the work I do I can actually get an accelerated viewport without maxing out the GPU's memory or spending $6k on a Quadro 6000.
The largest obstacle to wider use for me right now is Vray support. Hopefully Caustic and Vlado can work something out since I would really like it to support/accelerate Vray lights and materials.
The Caustic Series2 Ray Tracing Acceleration cards are PCIe add-in boards developed by the Caustic Professional group at Imagination Technologies. On the latest workstations, such as the HP Z620, they provide on average 2-5 times accelerated ray tracing (compared with CPU ray tracing) in popular 3D applications within Media & Entertainment and Computer Aided Design. With a Caustic Series2 card, 3D artists and designers can now have an interactive photorealistic viewport that is fully ray traced; from the earliest stages of modeling and look development. This saves the artist considerable time - reducing the number of preview renders necessary by catching potential problems with the modeling and look development of complex 3d scenes very early; before preview or final frame rendering.
Caustic Series2 includes the R2100 for single CPU workstations, and the R2500 for dual CPU workstations. When combined with Caustic Visualizer for Autodesk® Maya® and 3ds Max® or Neon for Rhino® 5.0, customers are able to work directly within a real-time photorealistic viewport. This enables them to introduce ray tracing much earlier into their content creation pipeline and iterate more rapidly without interrupting and slowing the creative process with time-consuming renders.