The latest Active Directory management pack deployment guide has a small section entitled "Enabling or Disabling Performance Data for Reports" and it was generating some good dialog internally between some colleagues and the product group. This section recommends that you disable the Performance monitor for the class "Active Directory Domain Controller Server 200x Computer Role" in order to minimize performance data collection for reports. However, this is a base aggregate monitor that is basically responsible for reflecting the best/worse case of health relative to the state of the child monitors. It has no direct impact on controlling the behavior of the child monitors, nor performance collection in general.
If you really want to disable performance data collection because reporting is not important to you, then you should be focusing on the performance collection rules. They are denoted as such with the words "performance collection" in the name of the respective rule. Examples in the ADMP are:
If you want to disable performance alerts because you are not concerned with certain performance issues with your DC's (as you may already know these facts and don't want to be constantly reminded), then you should be disabling the respective performance unit monitor. Examples in the ADMP are: