diff --git a/myhdl/_Signal.py b/myhdl/_Signal.py
index 8b3f6332..3d97b1ed 100644
--- a/myhdl/_Signal.py
+++ b/myhdl/_Signal.py
@@ -34,6 +34,7 @@ from myhdl import _simulator as sim
 from myhdl._simulator import _signals, _siglist, _futureEvents, now
 from myhdl._intbv import intbv
 from myhdl._bin import bin
+from myhdl._enum import EnumItemType
 
 _schedule = _futureEvents.append
 
@@ -145,7 +146,10 @@ class _Signal(object):
                 self._printVcd = self._printVcdHex
         else:
             self._type = type(val)
-            self._setNextVal = self._setNextType
+            if isinstance(val, EnumItemType):
+                self._setNextVal = self._setNextNonmutable
+            else:
+                self._setNextVal = self._setNextMutable
             if hasattr(val, '_nrbits'):
                 self._nrbits = val._nrbits
         self._eventWaiters = _WaiterList()
@@ -181,7 +185,7 @@ class _Signal(object):
                 self._val = None
             elif isinstance(val, intbv):
                 self._val._val = next._val
-            elif isinstance(val, (int, long)):
+            elif isinstance(val, (int, long, EnumItemType)):
                 self._val = next
             else:
                 self._val = deepcopy(next)
@@ -273,10 +277,15 @@ class _Signal(object):
         self._next._val = val
         self._next._handleBounds()
 
-    def _setNextType(self, val):
+    def _setNextNonmutable(self, val):
         if not isinstance(val, self._type):
             raise TypeError("Expected %s, got %s" % (self._type, type(val)))
-        self._next = deepcopy(val)      
+        self._next = val    
+        
+    def _setNextMutable(self, val):
+        if not isinstance(val, self._type):
+            raise TypeError("Expected %s, got %s" % (self._type, type(val)))
+        self._next = deepcopy(val)         
 
     # vcd print methods
     def _printVcdStr(self):
diff --git a/myhdl/test/benchmark/pypystats.dat b/myhdl/test/benchmark/pypystats.dat
index 27f98394..0baff155 100644
--- a/myhdl/test/benchmark/pypystats.dat
+++ b/myhdl/test/benchmark/pypystats.dat
@@ -3,39 +3,39 @@ Test: timer
 =====
 pypy
 ----
-real 82.32
-user 82.28
-sys 0.02
+real 81.87
+user 81.57
+sys 0.27
 
 Test: lfsr24
 =====
 pypy
 ----
-real 104.06
-user 104.00
-sys 0.03
+real 103.32
+user 103.09
+sys 0.21
 
 Test: randgen
 =====
 pypy
 ----
-real 90.33
-user 90.05
-sys 0.08
+real 89.86
+user 89.54
+sys 0.27
 
 Test: longdiv
 =====
 pypy
 ----
-real 87.96
-user 87.88
-sys 0.04
+real 88.03
+user 87.82
+sys 0.18
 
 Test: findmax
 =====
 pypy
 ----
-real 113.69
-user 113.62
-sys 0.03
+real 111.71
+user 111.48
+sys 0.19