An impact of configuration changes on controllers is projected, in a computing environment including one or more bridge attached channels. This projection quantifies the impact for each controller affected by the change, such that it is known by a quantifiable value how much the change impacts the controller. In order to project the impact, a projected I/O velocity of the controller is determined. In making the projections, pseudo channels associated with a particular bridge attached channel are modelled as independent channels. Alternatively, a utilization metric of a bridge attached channel is determined and compared to a threshold; pseudo channels associated with the bridge attached channel are modelled as independent channels if the utilization metric is below the threshold.