Multi provider query performance

I have created a multi provider which was originally a copy of an existing multi provider - I have replaced one of the info cubes with a different multi provider in the copy version. At present there is just a requirement to build one query off the multi provider. This requires a much smaller subset of characteristics to be identified in the multi provider compared to the original multi provider. How much impact does identification of more than required characteristics (I require 50 and at present there are 190) have on query performance? Thanks