6 Replies Latest reply on Oct 16, 2013 7:33 PM by Jerry Steiger

    Processor usage drops to zero during non-lin simulations

    Roy Dean

      I've noticed this, and even discussed it with Solidworks engineers.....


      While performing a "significant" non-linear simulation, occasionally my processor usage will drop to zero, and stay there for minutes at a time, before picking up and resuming the solution calculations.


      Why is solidworks doing this?   Note that it has nothing to do with the workstation, as I've seen this on multiple machines as well as manufacturers.   Seems like my solutions are taking twice as long as they should because my processor is getting "nap time"  during the solution.   I even have experienced processor usage dropping to zero and staying there indefinately (14+ hours of idle processor, all the while no errors or warnings from the solver.... just sits there and the "elapsed time" in the study solver window continues to tick even though all 8 processors are idle.....


      Anybody else experience this?   My reseller and solidworks haven't been able to offer any solutions.....

        • Re: Processor usage drops to zero during non-lin simulations
          Phil Perlich

          I'm sure you've checked this already, but make sure your results folder is on the hard drive of the machine performing the simulation.

          • Re: Processor usage drops to zero during non-lin simulations
            Jared Conway

            not all solving processes are multithreaded so i wouldn't expect them to all be going at full speed all the time.


            you mentioned you spoke with your reseller and solidworks, did they check the same problem on their system and confirm that it is a hardware/os/computer issue vs a software issue? you mentioned that you tested it, but if they tested it and saw the same issue, i have to believe if it was a software issue they would have given you an SPR, told you it was a limitation or given you an explanation like the one above.


            if this is happening on all files, i'd point to a hardware problem or os problem. and if that is the case, might as well post a sample file for somoene else to check.


            i'm also assuming this is latest version and service pack because there have been improvements in versions to use more cores..etc and also you've done standard hardware troubleshooting like disabling everything in msconfig, turning off hyperthreading, making sure the hardware is working properly..etc.

              • Re: Processor usage drops to zero during non-lin simulations
                Roy Dean

                Hi Jared.   I do recall sending sample files to either the reseller or DSS (or both), but never really got a response as to why it was happening.   I can't post a "sample" file, as these are pretty involved simulations.... the "simple ones" that actually solve don't exhibit this behavior typically.


                The ones that do solve AND demonstrate the behavior are considered corporate IP, so I can't really share them.    I'm just interested in seeing if others have experienced it.   Like I said previously, I've experienced this on a total of 4 workstations (two desktops, two laptops), and two different makes (lenovo and HP).


                I've seen it on 2012 and 2013 (SP4 currently).   This ONLY happens during non-linear simulations.   I can understand processor usage dropping, but droping to zero for up to 10 minutes at a time?

                  • Re: Processor usage drops to zero during non-lin simulations
                    Jared Conway

                    i can't say that i have ever had it drop to zero. but i also have an ssd, quad core, win 7 x64 and 24gb of ram. the only time i could see things dropping to zero is if some other process has priority or you're out of resources.


                    if you contacted your reseller or DSS, they would have issued an SPR if it was a software problem or even a file specific problem. and most likely provided you a workaround. so it seems strange that you didn't get anything back from them.


                    if you want another datapoint, feel free to contact me at jared@hawkridgesys.com and we can take a look at it on one of our systems.

                    • Re: Processor usage drops to zero during non-lin simulations
                      Jerry Steiger



                      I suspect that your system is writing files to disk during that time. I have very little experience with SolidWorks Simulation, but ANSYS often acts this way on my machine. Check out the disk activity in the Task Manager or the Resource Monitor. It could be saving intermediate results or possibly even swapping.


                      Jerry S.