There are some periodics in the Original Story that fire faster than once a second. The fastest one might be 0.33s, which is a number I chose because our Character Update tick rate is 0.3s, to which I add a small buffer. On a Character Update tick, vicinity, cansee, and distance key/values are updated, and various Should React to Reactions (event triggers) are checked (should character1 react to character2 being topless, if they're indeed topless, etc.), which effectively results in how fast characters react to things like "caught having sex", "caught masturbating", "exposes genitals", etc. The recently added "blinded" checks (from phones held by the player or an NPC) and the poked by vibrator checks also operate against this Character Update tick. Most importantly, the Event Handler Update and events handled within it (queued regular game events of any kind, AND periodic event triggers) can be updated at a speed
up to the Character Update tick rate.
So in short, the fastest periodics should
have to be is about 0.3s. It can be faster, but you won't gain anything. Notice the time delta on this periodic, which I set at 0.1s in the CSC:
Not firing every 0.1s. So, don't bother with anything faster than 0.3s. Again this only applies to game events that are queued (won't be getting into that whole system here, but it's safe to assume a fair amount are), and periodic event triggers. The actual *contents* of the event (like setting an NPC to state immobile = true) are generally instant or near-instant. As instant as your PC can get
Once these event "contents" fire, they're effectively ready to use in an event that is fired next OR perhaps more accurately stated: is next in the event queue. Even an event that is within the same periodic and merely one "Order" value higher (yes, Order matters other than OCD organization).
As for performance, there could be an affect with many periodics running at once. Especially if they display messages on-screen or aggressively handle character animation(s) or movement, or cause physics fun to happen. Things could also get choppy if you're handling large arrays of criteria at once and firing off many simple game events; but the threshold for for that is still higher than if you're trying to fire off momentum itemfunctions or something like that every 0.3s. Even if you have four events, one at 0.01s, 0.1s, 0.2s, and 0.3s as shown below, they'll only process at the rate of the Character Update tick rate, so you would have to try pretty hard to impact anyone with a relatively modern PC:
If you're concerned about it, set ALL of your periodic event triggers to false at the beginning of a story, set them to true when you are sure you'll need them soon or imminently, disable them when they'll definitely not be used again, AND criteria-lock them. If a periodic is not enabled, none of its criteria are evaluated and nothing inside it is evaluated or will have a chance at firing.