Dynamically assigning subcarriers of OFDM systems to multiple different terminals in a cell has been shown to be beneficial in terms of different transmission metrics. However, the success of such a scheme depends on the ability of the access point to inform terminals of their newest subcarrier assignments as well as on the accuracy of the channel state information used to generate new assignments. It is not clear whether the overhead required to implement these two system abilities consumes all of the potential performance increase possible by dynamically assigning subcarriers. In this paper, a specific MAC structure is selected enabling the operation of a dynamic OFDM system. Then, we study the question of the required overhead. A static assignment variant serves as a comparison scheme. We investigate the performance difference of these two schemes for various scenarios where at first signaling and then realistic channel knowledge is added to the system model. The results in terms of average throughput and goodput per terminal are obtained for a varying number of terminals in the cell as well as for a varying transmit power. We find that the performance is not only decreased for the dynamic scheme but also for the static one, such that the overall ratio favors the dynamic rather than the static scheme especially in realistic system environments. ; QC 20140103