diff --git a/GPy/core/parameterization/ties_and_remappings.py b/GPy/core/parameterization/ties_and_remappings.py
index 4da59237..8e5eed87 100644
--- a/GPy/core/parameterization/ties_and_remappings.py
+++ b/GPy/core/parameterization/ties_and_remappings.py
@@ -473,7 +473,7 @@ class Tie(Parameterized):
             self._untie_ = None
         else:
             self.label_buf = np.zeros((self._highest_parent_.param_array.size,),dtype=np.uint32)
-            self._traverse_param(lambda x:np.put(self.label_buf,self._highest_parent_._raveled_index_for(x),x.tie.flat), (self._highest_parent_,), [])
+            self._traverse_param(lambda x:np.put(self.label_buf,xrange(self._highest_parent_._offset_for(x),x.size),x.tie.flat), (self._highest_parent_,), [])
             self.buf_idx = self._highest_parent_._raveled_index_for(self.tied_param)
             self._untie_ = self.label_buf==0
             self._untie_[self.buf_idx] = True
@@ -577,26 +577,60 @@ class Tie(Parameterized):
         self.update_model(True)
         
     def _check_change(self):
-        changed = False
+        changed = [0]
         if self.tied_param is not None:
-            for i in xrange(self.tied_param.size):
-                b0 = self.label_buf==self.label_buf[self.buf_idx[i]]
-                b = self._highest_parent_.param_array[b0]!=self.tied_param[i]
-                if b.sum()==0:
-                    # All the tied parameters are the same
-                    continue
-                elif b.sum()==1:
-                    # One of the tied parameter is different.
-                    # It must be recently changed one.
-                    # The rest will be set to its value.
-                    val = self._highest_parent_.param_array[b0][b][0]
-                    self._highest_parent_.param_array[b0] = val
-                else:
-                    # It is most likely that the tie parameter is changed.
-                    # Set all the tied parameter to the value of tie parameter.
-                    self._highest_parent_.param_array[b0] = self.tied_param[i]
-                changed = True
-        return changed
+            
+            from scipy import weave
+            from ...util.misc import param_to_array
+            param_array = self._highest_parent_.param_array
+            tied_param = param_to_array(self.tied_param)
+            tie_l = np.zeros_like(tied_param,dtype=np.int)
+            t_pairs = self.tie_pairs
+            t_pairs_size = self.tie_pairs.size
+            code="""
+            for(int i=0;i<t_pairs_size;i+=2) {
+                int pidx = t_pairs[i];
+                int tidx = t_pairs[i+1];
+                if(param_array[pidx] != tied_param[tidx]) {
+                    if(tie_l[tidx]==0) {
+                        tie_l[tidx] = pidx;
+                    } else if(tie_l[tidx]>0) {
+                        tie_l[tidx] = -1;
+                    }
+                    changed[0] = 1;
+                }
+            }
+            for(int i=0;i<t_pairs_size;i+=2) {
+                int pidx = t_pairs[i];
+                int tidx = t_pairs[i+1];
+                if(tie_l[tidx]>0) {
+                    param_array[pidx] = param_array[tie_l[tidx]];
+                    tied_param[tidx] = param_array[pidx];
+                } else if(tie_l[tidx]==-1) {
+                    param_array[pidx] = tied_param[tidx];
+                }
+            }
+            """
+            weave.inline(code, arg_names=['param_array','t_pairs','t_pairs_size','tied_param','tie_l','changed'])
+
+#             for i in xrange(self.tied_param.size):
+#                 b0 = self.label_buf==self.label_buf[self.buf_idx[i]]
+#                 b = self._highest_parent_.param_array[b0]!=self.tied_param[i]
+#                 if b.sum()==0:
+#                     # All the tied parameters are the same
+#                     continue
+#                 elif b.sum()==1:
+#                     # One of the tied parameter is different.
+#                     # It must be recently changed one.
+#                     # The rest will be set to its value.
+#                     val = self._highest_parent_.param_array[b0][b][0]
+#                     self._highest_parent_.param_array[b0] = val
+#                 else:
+#                     # It is most likely that the tie parameter is changed.
+#                     # Set all the tied parameter to the value of tie parameter.
+#                     self._highest_parent_.param_array[b0] = self.tied_param[i]
+#                 changed = True
+        return False if changed[0]==0 else True
     
     def _parameters_changed_notification(self, me, which=None):
         if which is not self: