diff --git a/src/display.c b/src/display.c
index 40ee24f9e..d9cca8ec5 100644
--- a/src/display.c
+++ b/src/display.c
@@ -901,7 +901,7 @@ gboolean
 myDisplayTestXrender (DisplayInfo *display, gdouble min_time)
 {
 #ifdef HAVE_RENDER
-    GTimeVal t1, t2;
+    gint64 t1, t2;
     gdouble dt;
     Display *dpy;
     Picture picture1, picture2, picture3;
@@ -971,7 +971,7 @@ myDisplayTestXrender (DisplayInfo *display, gdouble min_time)
                                 DefaultRootWindow(dpy),
                                 1, 1, 8);
 
-    g_get_current_time (&t1);
+    t1 = g_get_monotonic_time ();
 
     pa.repeat = TRUE;
     picture1 = XRenderCreatePicture (dpy,
@@ -1011,10 +1011,8 @@ myDisplayTestXrender (DisplayInfo *display, gdouble min_time)
 
     XDestroyWindow (dpy, output);
 
-    g_get_current_time (&t2);
-
-    dt = (gdouble) (t2.tv_sec - t1.tv_sec) * G_USEC_PER_SEC +
-         (gdouble) (t2.tv_usec - t1.tv_usec) / 1000.0;
+    t2 = g_get_monotonic_time ();
+    dt = (gdouble) (t2 - t1) / 1000.0;
 
     if (dt < min_time)
     {
diff --git a/src/startup_notification.c b/src/startup_notification.c
index 4fc9e6af5..ece84ee2b 100644
--- a/src/startup_notification.c
+++ b/src/startup_notification.c
@@ -52,7 +52,7 @@ static SnDisplay *sn_display = NULL;
 typedef struct
 {
     GSList *list;
-    GTimeVal now;
+    gint64 now;
 }
 CollectTimedOutData;
 
@@ -139,9 +139,8 @@ sn_collect_timed_out_foreach (void *element, void *data)
     sn_startup_sequence_get_last_active_time (sequence, &l_sec, &l_usec);
     tv_sec = l_sec; tv_usec = l_sec;
 
-    elapsed =
-        ((((double) ctod->now.tv_sec - tv_sec) * G_USEC_PER_SEC +
-            (ctod->now.tv_usec - tv_usec))) / 1000.0;
+    elapsed = ((double) ctod->now - (tv_sec * G_USEC_PER_SEC) - tv_usec)
+        / 1000.0;
 
     if (elapsed > STARTUP_TIMEOUT)
     {
@@ -160,7 +159,7 @@ sn_startup_sequence_timeout (void *data)
     g_return_val_if_fail (screen_info != NULL, FALSE);
 
     ctod.list = NULL;
-    g_get_current_time (&ctod.now);
+    ctod.now = g_get_real_time ();
     g_slist_foreach (screen_info->startup_sequences, sn_collect_timed_out_foreach, &ctod);
 
     tmp = ctod.list;