title: Theano GPU Performance: Difference between theano.shared vs numpy.ndarray
body: <p>Several places mention that using shared variables improve performance when using a GPU (like <a href="http://deeplearning.net/software/theano/tutorial/aliasing.html" rel="nofollow">here</a>, or <a href="http://deeplearning.net/software/theano/tutorial/examples.html" rel="nofollow">here</a>). But I haven't been able to find any numbers quantifying the difference.</p>
  
  <p>Today I was told by a Professor at my school that I am basically wasting my time setting up shared variables, because the speed up in negligible.</p>
  
  <p>Are there any formal tests that you know of, or failing that what are your personal experiences/heuristics?</p>