better cudnn v2 doc

doc/library/sandbox/cuda/dnn.txt

@@ -34,6 +34,15 @@ Theano will still work if the user did not introduce them manually.
 To get an error if Theano can not use cuDNN, use this Theano flag:
 ``optimizer_including=cudnn``.
 
+.. note::
+
+   CuDNN v2 is now release, if you used any v2 release candidate, we
+   strongly suggest that you update it to the final version. From now
+   on, we only support the final release.
+
+   CuDNN v2 is much faster then v1. We recommand to every body to
+   update from v1 to v2.
+
 .. note::
 
     Normally you should not call GPU Ops directly, but the CPU interface
@@ -54,12 +63,6 @@ To get an error if Theano can not use cuDNN, use this Theano flag:
     There is a problem we do not understand yet when cudnn path are
     used with symbolic link. So avoid using that.
 
-.. note::
-
-   CuDNN v2 is now release, if you used any v2 release candidate, we
-   strongly suggest that you update it to the final version. From now
-   on, we only support the final release.
-
 
 Functions
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