diff --git wp-includes/pluggable.php wp-includes/pluggable.php
index ac308a9..464c5f9
--- wp-includes/pluggable.php
+++ wp-includes/pluggable.php
@@ -138,9 +138,15 @@ function get_user_by( $field, $value ) {
 	if ( !$userdata )
 		return false;
 
+	$user = wp_cache_get( $userdata->ID, 'users' );
+
+	if ( !empty( $user ) && !empty( $user->caps ) )
+		return $user;
+
 	$user = new WP_User;
 	$user->init( $userdata );
 
+	wp_cache_set( $userdata->ID, $user, 'users' );
 	return $user;
 }
 endif;