I do not have fritz 12 but cant you just download a very strong open source chess engine like stockfish , or houdini and just add it to the fritz interface,if the fritz engine is too weak for your tastes.
Fritz 12

I do not have fritz 12 but cant you just download a very strong open source chess engine like stockfish , or houdini and just add it to the fritz interface,if the fritz engine is too weak for your tastes.
You can. You could simply download Rybka 2.3.2a (it's free), and create an UCI engine. It'll work with your Fritz interface.

On the Hmbase site in germany the deep engines always outperform the regular engines by at least 100 to 1. Rybka deep core easily outperformes by about 1000 to 1 other peoples engines. And fritz 12 would easily beat rybka 2. Loses to rybka 3 and definitely cannot compete with rybka 4 in an engine match.
Does Fritz 12 ,Shredder or Rybka work on a Mac? If not what program would you recommend.