The total number of memory cells is 200 000. The number of memory cells may be increased when you order the equipment. You can change distribution of this memory between users and events by yourself. For instance, you can allot 100 000 cells for the storage of user data and other configuration and 100 000 cells for the storage of events.
The system also has memory of events for every key, i.e. the system stores last events for every key, irrespectively of how long ago this event took place.