in most cases I've seen mining techniques listed as either ATI with OpenCL or Nvidia with Cuda. but I have seen Nvidia graphics that claim to support OpenCL. is this implementation different or would the same miner that does OpenCL on ATI work just as well as OpenCL on Nvidia?
OpenCL is framework for heterogeneous computing, that is, a program written in
OpenCL should run on any plattform that supports it, and
Nvidia does, among a wide range.
The main benefit of
OpenCL is the ability to write the code once and to be able to run it on different platforms without changes. Normally that comes with a performance cost.
So there's a tradeoff between performance and savings in code maintenance and developing efforts. I.e, OpenCL could be a reasonable framework for a generic miner but if you are devoted to squeeze any performance bit you can, IMO you should rely on the native framework for that platform, i.e