Index: virt-manager-1.0.1/virtinst/guest.py
===================================================================
--- virt-manager-1.0.1.orig/virtinst/guest.py
+++ virt-manager-1.0.1/virtinst/guest.py
@@ -346,6 +346,12 @@ class Guest(XMLBuilder):
         self.on_reboot = action
         self.on_crash = action
 
+        # At install time only set the target disk to 'unsafe' for
+        # better performance
+        if install:
+            target_disk = self.get_devices("disk")[0]
+            saved_cache = target_disk.driver_cache
+            target_disk.driver_cache = "unsafe"
         self._set_defaults()
 
         self.bootloader = None
@@ -365,7 +371,10 @@ class Guest(XMLBuilder):
                 self.bootloader = "/usr/bin/pygrub"
                 self.os.clear()
 
-        return self.get_xml_config()
+        xml_config = self.get_xml_config()
+        if install:
+            target_disk.driver_cache = saved_cache
+        return xml_config
 
     def get_continue_inst(self):
         """