title: Memory bandwidth test on Nvidia GPU's
body: <p>I tried to use the code posted by nvidia and do a memory bandwidth test but i got some surprising results </p>
  
  <p>Program used is here : <a href="https://developer.nvidia.com/content/how-optimize-data-transfers-cuda-cc" rel="nofollow">https://developer.nvidia.com/content/how-optimize-data-transfers-cuda-cc</a></p>
  
  <p>On a Desktop (with MacOS)</p>
  
  <pre><code>Device: GeForce GT 650M
  Transfer size (MB): 16
  
  Pageable transfers
  Host to Device bandwidth (GB/s): 4.053219
  Device to Host bandwidth (GB/s): 5.707841
  
  Pinned transfers
  Host to Device bandwidth (GB/s): 6.346621
  Device to Host bandwidth (GB/s): 6.493052
  </code></pre>
  
  <p>On a Linux server :</p>
  
  <pre><code>Device: Tesla K20c
  Transfer size (MB): 16
  
  Pageable transfers
  Host to Device bandwidth (GB/s): 1.482011
  Device to Host bandwidth (GB/s): 1.621912
  
  Pinned transfers
  Host to Device bandwidth (GB/s): 1.480442
  Device to Host bandwidth (GB/s): 1.667752
  </code></pre>
  
  <p>BTW i do not have the root privilege.. </p>
  
  <p>I am not sure why its less on the tesla device.. Can anyone point out what would be the reason ? </p>