diff --git a/API-Event.md b/API-Event.md
index 5d8bd9e..78e1d57 100644
--- a/API-Event.md
+++ b/API-Event.md
@@ -6,7 +6,8 @@ This API provides a rudimentary event system. It is primarily intended to be use
   Unregister a previously registered event listener. Returns `true` if the event listener was removed, `false` if the listener was not registered.
 - `event.timer(interval: number, callback: function[, times: number]): number`  
   Starts a new timer that will be called after the time specified in `interval`. Per default, timers only fire once. Pass `times` with a value larger than one to have it fire as often as that number specifies. Pass `math.huge` to create an infinitely repeating interval.  
-  This returns a number that identifies the created timer, and can be used in `timer.cancel` to destroy it, possibly before it even ran once.
+  This returns a number that identifies the created timer, and can be used in `timer.cancel` to destroy it, possibly before it even ran once.  
+  *Note*: the timer resolution can vary. If the computer is idle and enters sleep mode, it will only be woken in a game tick, so the time the callback is called may be up to 0.05 seconds off.  
   **Important**: timers are driven by the `event.pull` function. If you always pull signals directly from `os.pullSignal` and never call `event.pull`, timers will not work!
 - `event.cancel(timerId: function): boolean`  
   Cancels a timer previously created with `event.timer`. Returns `true` if the timer was stopped, `false` if there was no timer with the specified ID.