Some embodiments of the invention accurately account for power dissipation in memory systems that include individual memory modules by keeping track of the number of read requests, the number of write requests, and the number of activate requests that are applied to the individual memory modules during selected time periods. If the sum of these totals exceeds a threshold level, the embodiments throttle the memory system, either by throttling the entire memory system based in response to the most active memory module, or by throttling individual memory modules as needed. Other embodiments of the invention may assign the same or different weights to activate requests, read requests, and write requests. Other embodiments are described and claimed.