Good day
You can edit the RenderStyle.
but first you can do quick renders with a lower dpi/res setting render like Fast with shadows, know it will look like what you want it and then do a final render. When you ready and happy with your drawing setup and renderstyle, instead of rendering on screen completely, hit the Esc button after you have told it to Render, you might need to hold it down for a few seconds to clear the command, to stop the render and then Save to PDF.
There are tons more things you can do to alter the drawing to speed up the Render process, like the way you apply textures, using square tube truss instead of round, Editing the lights, making sure the ones in the drawing are actually been seen and used as a possitive effect in the Render.
Post up what your system specs are in your Signature so we can help you more. also what version did you use previously? 2011/2012 is Totally different than the VWv.11/12 in the rendering field as it is now running on C4D...