title: multithreading ghostscript with dNumRenderingThreads=4 NO SPEED IMPROVEMENT
body: <p>I'm trying to render .pdf to .png file using multithreaded ghostscript 9.07. Installed from .exe file.
  For this I call following procedure:</p>
  
  <pre><code>gswin64c.exe -dNumRenderingThreads=4 -dSAFER -dBATCH -dNOPAUSE -sDEVICE=png16m -r300 -sOutputFile=Graphic1.png Graphic1.pdf
  </code></pre>
  
  <p>My system is Windows 8 x64 running on quad core AMD phenom II processor and my test graphic is single page 109 MB pdf.</p>
  
  <p>The procedure is processing the same time (about 32s for 300 dpi) regardless of whether the dNumRenderingThreads is set or not. What's more  windows task manager shows that gs process uses only 2 threads (one for parsing and one for rednering as far as I know)</p>
  
  <p>What am I doing wrong that rendering is not spread on many threads?</p>