Index: src/wp-includes/widgets.php
===================================================================
--- src/wp-includes/widgets.php	(revision 26983)
+++ src/wp-includes/widgets.php	(working copy)
@@ -125,9 +125,14 @@
 	// Private Functions. Don't worry about these.
 
 	function _register() {
-		$settings = $this->get_settings();
+		$settings = false;
 		$empty = true;
 
+		// Prefetch settings only for widgets that are used (whether active or inactive)
+		if ( is_active_widget( false, false, $this->id_base, false ) ) {
+			$settings = $this->get_settings();
+		}
+
 		if ( is_array($settings) ) {
 			foreach ( array_keys($settings) as $number ) {
 				if ( is_numeric($number) ) {