Index: wp-content/plugins/akismet/akismet.php
===================================================================
--- wp-content/plugins/akismet/akismet.php	(revision 355641)
+++ wp-content/plugins/akismet/akismet.php	(working copy)
@@ -202,8 +202,7 @@
 }
 
 function akismet_microtime() {
-	$mtime = explode( ' ', microtime() );
-	return $mtime[1] + $mtime[0];
+	return microtime( true );
 }
 
 // log an event for a given comment, storing it in comment_meta
Index: wp-includes/load.php
===================================================================
--- wp-includes/load.php	(revision 17501)
+++ wp-includes/load.php	(working copy)
@@ -186,8 +186,7 @@
  */
 function timer_start() {
 	global $timestart;
-	$mtime = explode( ' ', microtime() );
-	$timestart = $mtime[1] + $mtime[0];
+	$timestart = microtime( true );
 	return true;
 }
 
@@ -217,9 +216,7 @@
  */
 function timer_stop( $display = 0, $precision = 3 ) { // if called like timer_stop(1), will echo $timetotal
 	global $timestart, $timeend;
-	$mtime = microtime();
-	$mtime = explode( ' ', $mtime );
-	$timeend = $mtime[1] + $mtime[0];
+	$timeend = microtime( true );
 	$timetotal = $timeend - $timestart;
 	$r = ( function_exists( 'number_format_i18n' ) ) ? number_format_i18n( $timetotal, $precision ) : number_format( $timetotal, $precision );
 	if ( $display )
Index: wp-includes/wp-db.php
===================================================================
--- wp-includes/wp-db.php	(revision 17501)
+++ wp-includes/wp-db.php	(working copy)
@@ -1444,8 +1444,7 @@
 	 * @return true
 	 */
 	function timer_start() {
-		$mtime            = explode( ' ', microtime() );
-		$this->time_start = $mtime[1] + $mtime[0];
+		$this->time_start = microtime( true );
 		return true;
 	}
 
@@ -1457,10 +1456,8 @@
 	 * @return int Total time spent on the query, in milliseconds
 	 */
 	function timer_stop() {
-		$mtime      = explode( ' ', microtime() );
-		$time_end   = $mtime[1] + $mtime[0];
-		$time_total = $time_end - $this->time_start;
-		return $time_total;
+		$time_total = microtime( true ) - $this->time_start;
+		return (int) $time_total;
 	}
 
 	/**