Working in Inventor can be a wonderful experience but sometimes you will have some hiccups along the way especially when it comes to time to output render as well as slowness when viewing the results of an analysis.
A source of information that I use is Autodesk University. This is a treasure trove of webinars and information that will assist in nearly any workflow you are trying to come up with that involves Autodesk software. The beauty of this website is that it is updated with webinars every year whether it be from whats new, workflows between Revit and Inventor or even just think tanks on where your industry is going and how Autodesk is looking at impacting you in the future. Saying that I found some interesting tips on how to make my life easier when it comes to getting out quicker results for my Nastran analysis.
For the number of processors that are used for the analysis the default for Nastran is either 2 or 4 depending on your PC. If you look at the below graphic you will see that mine is set to 4 and I have 12 at my disposal. Upping this would definitely crunch the numbers quicker so where do i set this?

For the current analysis you have created, you can right click on the parameters option and change the nprocessors field. I have changed mine to 10 to leave a little processor power for other work to be conducted.

This was a little tip that I got from Autodesk University to assist with getting my simulations out little quicker each time.
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