diff --git a/src/main/java/com/sk89q/craftbook/core/st/SelfTriggeringManager.java b/src/main/java/com/sk89q/craftbook/core/st/SelfTriggeringManager.java
index c207f30ec..893329584 100644
--- a/src/main/java/com/sk89q/craftbook/core/st/SelfTriggeringManager.java
+++ b/src/main/java/com/sk89q/craftbook/core/st/SelfTriggeringManager.java
@@ -91,31 +91,16 @@ public Collection<Location> getSelfTriggeringMechanics() {
     private Location[] registeredLocations;
     private boolean hasChanged = false;
 
-    private boolean areAdjacentChunksLoaded(Location loc) {
+    private static boolean areAdjacentChunksLoaded(Location loc) {
         World world = loc.getWorld();
 
         final int CX = loc.getBlockX() >> 4;
         final int CZ = loc.getBlockZ() >> 4;
 
-        for (int x = -1; x <= 1; ++x) {
-            for (int z = -1; z <= 1; ++z) {
-                // Check only cardinal directions
-                if (x != 0 && z != 0) {
-                    continue;
-                }
-
-                // Don't test the current chunk
-                if (x == 0 && z == 0) {
-                    continue;
-                }
-
-                if (!world.isChunkLoaded(CX + x, CZ + z)) {
-                    return false;
-                }
-            }
-        }
-
-        return true;
+        return world.isChunkLoaded(CX - 1, CZ)
+                && world.isChunkLoaded(CX + 1, CZ)
+                && world.isChunkLoaded(CX, CZ - 1)
+                && world.isChunkLoaded(CX, CZ + 1);
     }
 
     /**
diff --git a/src/main/java/com/sk89q/craftbook/mechanics/ic/ICMechanic.java b/src/main/java/com/sk89q/craftbook/mechanics/ic/ICMechanic.java
index f930aaa7f..f95a8612e 100644
--- a/src/main/java/com/sk89q/craftbook/mechanics/ic/ICMechanic.java
+++ b/src/main/java/com/sk89q/craftbook/mechanics/ic/ICMechanic.java
@@ -16,6 +16,8 @@
 
 package com.sk89q.craftbook.mechanics.ic;
 
+import com.google.common.cache.Cache;
+import com.google.common.cache.CacheBuilder;
 import com.sk89q.craftbook.AbstractCraftBookMechanic;
 import com.sk89q.craftbook.ChangedSign;
 import com.sk89q.craftbook.CraftBookPlayer;
@@ -37,6 +39,7 @@
 import com.sk89q.worldedit.bukkit.BukkitAdapter;
 import org.apache.commons.lang.StringUtils;
 import org.bukkit.Bukkit;
+import org.bukkit.Location;
 import org.bukkit.block.Block;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.EventPriority;
@@ -47,6 +50,7 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Locale;
+import java.util.concurrent.TimeUnit;
 import java.util.regex.Matcher;
 
 /**
@@ -303,10 +307,27 @@ public void onThink(SelfTriggerThinkEvent event) {
 
         if(!EventUtil.passesFilter(event)) return;
 
+        // Cached fast path: think without re-snapshotting and re-parsing the sign.
+        Location loc = event.getBlock().getLocation();
+        ICFamily cachedFamily = thinkFastCache.getIfPresent(loc);
+        if (cachedFamily != null && ICManager.isCachedIC(loc)) {
+            IC cachedIC = ICManager.getCachedIC(loc);
+            if (cachedIC instanceof SelfTriggeredIC selfTriggeredIC) {
+                event.setHandled(true);
+                ChipState chipState = cachedFamily.detectSelfTriggered(BukkitAdapter.adapt(loc), cachedIC.getSign());
+                selfTriggeredIC.think(chipState);
+                try {
+                    cachedIC.getSign().update(false);
+                } catch (Throwable ignored) {}
+                return;
+            }
+        }
+
         final Object[] icData = setupIC(event.getBlock(), true);
 
         if(icData != null && icData[2] instanceof SelfTriggeredIC ic) {
             event.setHandled(true);
+            thinkFastCache.put(loc, (ICFamily) icData[1]);
             ChipState chipState = ((ICFamily) icData[1]).detectSelfTriggered(BukkitAdapter.adapt(event.getBlock().getLocation()), ((IC) icData[2]).getSign());
             ic.think(chipState);
             try {
@@ -315,6 +336,17 @@ public void onThink(SelfTriggerThinkEvent event) {
         }
     }
 
+    /**
+     * Location -> ICFamily for the think fast path. The expiry is what reruns
+     * the full setupIC verification, so a sign edited in place is picked up
+     * within a second; eviction bounds the map on a server with more ICs than
+     * this.
+     */
+    private final Cache<Location, ICFamily> thinkFastCache = CacheBuilder.newBuilder()
+            .maximumSize(4096)
+            .expireAfterWrite(1, TimeUnit.SECONDS)
+            .build();
+
     @EventHandler(priority = EventPriority.HIGH)
     public void onBlockBreak(BlockBreakEvent event) {