diff --git a/wp-includes/default-widgets.php b/wp-includes/default-widgets.php
index 7d06991a5b..2cb8c6c0f6 100644
--- a/wp-includes/default-widgets.php
+++ b/wp-includes/default-widgets.php
@@ -558,7 +558,7 @@ class WP_Widget_Recent_Posts extends WP_Widget {
 		endif;
 
 		$cache[$args['widget_id']] = ob_get_flush();
-		wp_cache_add('widget_recent_posts', $cache, 'widget');
+		wp_cache_set('widget_recent_posts', $cache, 'widget');
 	}
 
 	function update( $new_instance, $old_instance ) {
diff --git a/wp-includes/general-template.php b/wp-includes/general-template.php
index cbff39f02f..a1eabca6c1 100644
--- a/wp-includes/general-template.php
+++ b/wp-includes/general-template.php
@@ -906,7 +906,7 @@ function wp_get_archives($args = '') {
 		if ( !isset( $cache[ $key ] ) ) {
 			$arcresults = $wpdb->get_results($query);
 			$cache[ $key ] = $arcresults;
-			wp_cache_add( 'wp_get_archives', $cache, 'general' );
+			wp_cache_set( 'wp_get_archives', $cache, 'general' );
 		} else {
 			$arcresults = $cache[ $key ];
 		}
@@ -928,7 +928,7 @@ function wp_get_archives($args = '') {
 		if ( !isset( $cache[ $key ] ) ) {
 			$arcresults = $wpdb->get_results($query);
 			$cache[ $key ] = $arcresults;
-			wp_cache_add( 'wp_get_archives', $cache, 'general' );
+			wp_cache_set( 'wp_get_archives', $cache, 'general' );
 		} else {
 			$arcresults = $cache[ $key ];
 		}
@@ -949,7 +949,7 @@ function wp_get_archives($args = '') {
 		if ( !isset( $cache[ $key ] ) ) {
 			$arcresults = $wpdb->get_results($query);
 			$cache[ $key ] = $arcresults;
-			wp_cache_add( 'wp_get_archives', $cache, 'general' );
+			wp_cache_set( 'wp_get_archives', $cache, 'general' );
 		} else {
 			$arcresults = $cache[ $key ];
 		}
@@ -972,7 +972,7 @@ function wp_get_archives($args = '') {
 		if ( !isset( $cache[ $key ] ) ) {
 			$arcresults = $wpdb->get_results($query);
 			$cache[ $key ] = $arcresults;
-			wp_cache_add( 'wp_get_archives', $cache, 'general' );
+			wp_cache_set( 'wp_get_archives', $cache, 'general' );
 		} else {
 			$arcresults = $cache[ $key ];
 		}
@@ -1002,7 +1002,7 @@ function wp_get_archives($args = '') {
 		if ( !isset( $cache[ $key ] ) ) {
 			$arcresults = $wpdb->get_results($query);
 			$cache[ $key ] = $arcresults;
-			wp_cache_add( 'wp_get_archives', $cache, 'general' );
+			wp_cache_set( 'wp_get_archives', $cache, 'general' );
 		} else {
 			$arcresults = $cache[ $key ];
 		}