“In the past, back when servers had less computing power than phones nowadays have, these windows could be very large, with some games having up to 200ms windows of batching, including WoW. With better technology and servers, this system was improved over the years and, while it still exists, and effects from it can still be seen, the windows are much smaller, being 20ms wide for abilities in retail WoW. This means that abilities cast within 20ms of each other are considered simultaneous in the eyes of the retail WoW servers, while this window was about 200ms during Vanilla.”