title: Tensorflow takes >1 min on first run on video card with 5.0 compute capability
body: <p>I'm running tensorflow 0.8.0 for python3 (pip installation), and the following file <code>test.py</code>:</p>
  
  <pre><code>import tensorflow as tf                                                         
  
  a = tf.convert_to_tensor([1], dtype=tf.int32)                               
  b = tf.to_float(a)                                                              
  
  with tf.Session():                                                              
      b.eval() 
  </code></pre>
  
  <p>... takes more than a minute to run: </p>
  
  <pre><code>$time python3 test.py 
  I tensorflow/stream_executor/dso_loader.cc:105] successfully opened CUDA library libcublas.so locally
  I tensorflow/stream_executor/dso_loader.cc:105] successfully opened CUDA library libcudnn.so locally
  I tensorflow/stream_executor/dso_loader.cc:105] successfully opened CUDA library libcufft.so locally
  I tensorflow/stream_executor/dso_loader.cc:105] successfully opened CUDA library libcuda.so.1 locally
  I tensorflow/stream_executor/dso_loader.cc:105] successfully opened CUDA library libcurand.so locally
  I tensorflow/stream_executor/cuda/cuda_gpu_executor.cc:900] successful NUMA node read from SysFS had negative value (-1), but there must be at least one NUMA node, so returning NUMA node zero
  I tensorflow/core/common_runtime/gpu/gpu_init.cc:102] Found device 0 with properties: 
  name: GeForce GTX 860M
  major: 5 minor: 0 memoryClockRate (GHz) 1.0195
  pciBusID 0000:01:00.0
  Total memory: 4.00GiB
  Free memory: 3.61GiB
  I tensorflow/core/common_runtime/gpu/gpu_init.cc:126] DMA: 0 
  I tensorflow/core/common_runtime/gpu/gpu_init.cc:136] 0:   Y 
  I tensorflow/core/common_runtime/gpu/gpu_device.cc:755] Creating TensorFlow device (/gpu:0) -&gt; (device: 0, name: GeForce GTX 860M, pci bus id: 0000:01:00.0)
  
  real    1m6.985s
  user    1m6.700s
  sys 0m1.480s
  </code></pre>
  
  <p>I should mention other tensorflow programs seem to work fine, e.g. </p>
  
  <pre><code>$time python3 -m tensorflow.models.image.mnist.convolutional
  </code></pre>
  
  <p>takes under 4 minutes.</p>
  
  <p>Edit:</p>
  
  <pre><code>$cat /usr/local/cuda/version.txt 
  CUDA Version 7.5.18
  
  $ls /usr/local/cuda/lib64/libcudnn*
  /usr/local/cuda/lib64/libcudnn.so /usr/local/cuda/lib64/libcudnn.so.4.0.7
  /usr/local/cuda/lib64/libcudnn.so.4 /usr/local/cuda/lib64/libcudnn_static.a
  </code></pre>