diff --git a/src/core.cc b/src/core.cc
index 19d02da..6778d7c 100644
--- a/src/core.cc
+++ b/src/core.cc
@@ -17,6 +17,8 @@
 #include <limits.h>
 #include <string.h>
 
+static void idleImpl();
+
 // 0x51E234
 IdleFunc* _idle_func = NULL;
 
@@ -411,6 +413,10 @@ int coreInit(int a1)
     gTickerListHead = NULL;
     gScreenshotKeyCode = KEY_ALT_C;
 
+    // SFALL: Set idle function.
+    // CE: Prevents frying CPU when window is not focused.
+    inputSetIdleFunc(idleImpl);
+
     return 0;
 }
 
@@ -4907,3 +4913,8 @@ void convertMouseWheelToArrowKey(int* keyCodePtr)
         }
     }
 }
+
+static void idleImpl()
+{
+    SDL_Delay(125);
+}