Last week I purchased another 8800 GT. Although I would really like a 280 GT they are just too expensive and by buying another 8800 I can play with multiple GPU code. After some initial teething problems with video drivers and my machine going blue screen all the time I have the 2 cards working happily. Unfortunately my machine dropped from x16 pcie to x8 to each card. This is not too serious for me as I don't move too much data over the bus between cycles (apart from the rendered image).
Using two cards gives a lot of flexibility as you can essentially run two kernels at once (Same or different ones). Currently I'm playing with each card rendering half the screen and then stitching them back together on the primary card.
The api I am developing for molecular visualization will now get support for multiple gpus thus fitting in rather nicely to the launch of the Tesla personal supercomputers. Somehow I got invited to the launch of these beasts next week. I'll be sure to post about that.
As mentioned in the title "Tracelight" will be the new name for "cudart" due largely to the fact that cudart.dll is a cuda dll and a lot of confusion has resulted. When I originally thought of the name I didn't realize the naming conflict. As a result there are a large amount of search hits on this site for cudart help referring to problems with the dll installation rather than ray tracing related searches.
Expect some more demos of tracelight soon from both the molecular api branch and the triangle mesh branch. It has its own domain (www.tracelight.co.uk) but for now just links back to www.bv2.co.uk