CUDA-related specs by device?

Hello–

Is there a page on nVidia’s website detailing CUDA-related hardware specs?

I have a GTX 280 and all I can find are general specs on this page:

http://www.nvidia.com/object/product_geforce_gtx_280_us.html

For example–I know in the GeForce 8- series there are 512 threads allowed per block and 32 threads in a wrap.

Are these different for other cards? Where can I go for this information?

Also does anyone have experience across multiple cards? What tends to “work well”? More cores, more ram, etc? What’s the biggest bang-for-buck consideration when buying a new card?

Thanks
Alan

There is a summary of the specifications of the different generations of multiprocessor hardware in the rear of the programming guide.