diff -u b/includes/module.inc b/includes/module.inc
--- b/includes/module.inc
+++ b/includes/module.inc
@@ -712,6 +712,7 @@
   if ($reset) {
     $implementations = array();
     cache_set('module_implements', array(), 'cache_bootstrap');
+    drupal_static_reset('_module_implements_get_implementations');
     drupal_static_reset('module_hook_info');
     drupal_static_reset('drupal_alter');
     cache_clear_all('hook_info', 'cache_bootstrap');
@@ -720,13 +721,7 @@
 
   // Fetch implementations from cache.
   if (empty($implementations)) {
-    $implementations = cache_get('module_implements', 'cache_bootstrap');
-    if ($implementations === FALSE) {
-      $implementations = array();
-    }
-    else {
-      $implementations = $implementations->data;
-    }
+    $implementations = _module_implements_get_implementations();
   }
 
   if (!isset($implementations[$hook])) {
@@ -775,6 +770,38 @@
 }
 
 /**
+ * Helper function that gets the module implementations from cache.
+ *
+ * @return array
+ *   The module implementations.
+ */
+function _module_implements_get_implementations() {
+  $implementations_cached = &drupal_static(__FUNCTION__);
+  // Try to fetch the implementations from static cache.
+  if (isset($implementations_cached)) {
+    $implementations = $implementations_cached;
+  }
+  // Otherwise, get the implementations from the cache backend.
+  else {
+    $implementations = cache_get('module_implements', 'cache_bootstrap');
+    if ($implementations === FALSE) {
+      $implementations = array();
+    }
+    else {
+      // Set up the implementations variable.
+      $implementations = $implementations->data;
+
+      // Because we reset the "module_implements" static at the end of the
+      // bootstrap, we store the cache result into another static variable
+      // so as to prevent having a second cache_get() in case
+      // module_implements() is called early in the bootstrap.
+      // @see _drupal_bootstrap_full()
+      $implementations_cached = $implementations;
+    }
+  }
+}
+
+/**
  * Retrieves a list of hooks that are declared through hook_hook_info().
  *
  * @return