diff --git a/src/up-daemon.c b/src/up-daemon.c
index 38d49d5..be47ba8 100644
--- a/src/up-daemon.c
+++ b/src/up-daemon.c
@@ -474,28 +474,29 @@ up_daemon_enumerate_devices (UpExportedDaemon *skeleton,
 {
 	guint i;
 	GPtrArray *array;
-	GPtrArray *object_paths;
 	UpDevice *device;
+	const gchar **object_paths;
+	guint num_devices;
 
 	/* build a pointer array of the object paths */
-	object_paths = g_ptr_array_new_with_free_func (g_free);
 	array = up_device_list_get_array (daemon->priv->power_devices);
+	num_devices = array->len;
+	object_paths = g_newa (const gchar *, num_devices + 1);
+	num_devices = 0;
 	for (i = 0; i < array->len; i++) {
-		const char *object_path;
+		const gchar *object_path;
 		device = (UpDevice *) g_ptr_array_index (array, i);
 		object_path = up_device_get_object_path (device);
 		if (object_path != NULL)
-			g_ptr_array_add (object_paths, g_strdup (object_path));
+			object_paths[num_devices++] = object_path;
 	}
+	object_paths[num_devices] = NULL;
 	g_ptr_array_unref (array);
-	g_ptr_array_add (object_paths, NULL);
 
 	/* return it on the bus */
 	up_exported_daemon_complete_enumerate_devices (skeleton, invocation,
-						       (const gchar **) object_paths->pdata);
+						       object_paths);
 
-	/* free */
-	g_ptr_array_unref (object_paths);
 	return TRUE;
 }
 
@@ -506,28 +507,29 @@ up_daemon_enumerate_kbd_backlights (UpExportedDaemon *skeleton,
 {
 	guint i;
 	GPtrArray *array;
-	GPtrArray *object_paths;
 	UpDeviceKbdBacklight *kbd_backlight;
+	const gchar **object_paths;
+	guint num_devices;
 
 	/* build a pointer array of the object paths */
-	object_paths = g_ptr_array_new_with_free_func (g_free);
 	array = up_device_list_get_array (daemon->priv->kbd_backlight_devices);
+	num_devices = array->len;
+	object_paths = g_newa (const gchar *, num_devices + 1);
+	num_devices = 0;
 	for (i = 0; i < array->len; i++) {
-		const char *object_path;
+		const gchar *object_path;
 		kbd_backlight = (UpDeviceKbdBacklight *) g_ptr_array_index (array, i);
 		object_path = up_device_kbd_backlight_get_object_path (kbd_backlight);
 		if (object_path != NULL)
-			g_ptr_array_add (object_paths, g_strdup (object_path));
+			object_paths[num_devices++] = object_path;
 	}
+	object_paths[num_devices] = NULL;
 	g_ptr_array_unref (array);
-	g_ptr_array_add (object_paths, NULL);
 
 	/* return it on the bus */
 	up_exported_daemon_complete_enumerate_kbd_backlights (skeleton, invocation,
-							      (const gchar **) object_paths->pdata);
+							      object_paths);
 
-	/* free */
-	g_ptr_array_unref (object_paths);
 	return TRUE;
 }
 
diff --git a/src/up-device.c b/src/up-device.c
index 2a5ff1a..6ce9026 100644
--- a/src/up-device.c
+++ b/src/up-device.c
@@ -309,6 +309,7 @@ up_device_get_id (UpDevice *device)
 	const char *model;
 	const char *serial;
 	UpExportedDevice *skeleton;
+	char string_buf[256];
 
 	if (priv->native == NULL)
 		return NULL;
@@ -325,7 +326,7 @@ up_device_get_id (UpDevice *device)
 		if (!up_exported_device_get_is_present (skeleton))
 			goto out;
 
-		string = g_string_new ("");
+		string = g_string_new_len (string_buf, sizeof (string_buf));
 
 		/* in an ideal world, model-capacity-serial */
 		if (model != NULL && strlen (model) > 2) {
@@ -355,7 +356,7 @@ up_device_get_id (UpDevice *device)
 
 	} else {
 		/* generic fallback, get what data we can */
-		string = g_string_new ("");
+		string = g_string_new_len (string_buf, sizeof (string_buf));
 		if (up_exported_device_get_vendor (skeleton) != NULL) {
 			g_string_append (string, up_exported_device_get_vendor (skeleton));
 			g_string_append_c (string, '-');