Index: virt-manager-1.1.0/virtinst/guest.py
===================================================================
--- virt-manager-1.1.0.orig/virtinst/guest.py
+++ virt-manager-1.1.0/virtinst/guest.py
@@ -32,6 +32,7 @@ from virtinst import util
 from virtinst import support
 from virtinst import OSXML
 from virtinst import VirtualDevice
+from virtinst import VirtualDisk
 from virtinst import Clock
 from virtinst import Seclabel
 from virtinst import CPU
@@ -349,6 +350,13 @@ class Guest(XMLBuilder):
         self.on_crash = action
 
         self._set_defaults()
+        # At install time set the target disk to 'unsafe' for
+        # better performance if the target is not a block device
+        if install:
+            target_disk = self.get_devices("disk")[0]
+            saved_cache = target_disk.driver_cache
+            if target_disk.type != VirtualDisk.TYPE_BLOCK:
+                target_disk.driver_cache = VirtualDisk.CACHE_MODE_UNSAFE
 
         self.bootloader = None
         if (not install and
@@ -367,7 +375,10 @@ 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):
         """