DebbieKat
We have been using Informatica Powermart 5.1 with Oracle 8.1.7 successfully with over 400 fields in one mapping. Apart from being slow, this has caused one significant problem - the debugger will not work. We found that this wasn't a show stopper, but given the complexity of the mapping, it was very difficult to debug - so it required a very good test team to throw the right data at the mapping, so we could isolate problems in the logic as and when it occurred.
Hope this helps
regards
Mark