5 Replies Latest reply on Feb 9, 2018 8:22 AM by Michael Dirisio

    Strange goings on in output rendering.

    Alexander Smith

      Hi Everyone and a belated happy new year.


      I am stretching my new setup by making it do a decent sized render but am experiencing some really strange issues shown in the attached screen grab of my task manager. I chose the render as GPU (graphics card) only but the task manager shows only 1% of usage on the GPU and maxing out at 99, 95% on the CPU.


      Admittedly the render setup is big but the polygon rate is well well within tolerance.

      3507 x 2480px (A4).


      7000 passes

      Bloom enabled

      Depth Of Field enabled


      I rendered the same spec' as above without bloom and DOF as a test and it rendered in about 6-7 hours I think which is still a long time to my mind. This one has been going 19 hours and says that it will be another 6!!


      So the questions are twofold.


      1. Does Bloom and DOF really require so much more calculation that it slow down a render by almost 3 quarters.

      2. Why when I ask it to render with GPU only, is the GPU performing so little and the CPU maxing out?


      Main parts of spec' is as follows.

      Intel® Core™i7 Quad Core Processor i7-7700k (4.2GHz) 8MB Cache

      32GB Corsair VENGEANCE DDR4 3000MHz (2 x 16GB)

      PNY QUADRO P5000 16GB GDDR5, 2560 CUDA CORES - 4 x DP, 1 x DVI-D


      Is the CPU just not up to it??



        • Re: Strange goings on in output rendering.
          Ron Bates

          1. Bloom will not add much as it's a post process (done quickly after render is complete).  But DOF can be quite expensive.  The larger the output, the more expensive.  And the more time..  BUT, refer to next point regarding the likely culprit of the main performance issue...


          2. I suspect your system is running out of GPU memory, and silently falling back to CPU only rendering.  (What GPU is in your system?)


          This can be quite common actually.  We are working with nVidia on ways to provide more direct feedback that this has occurred.  At the moment, it's happening silently (so your render will simply continue) and you'll see no indication except:

          • Log files will indicate your GPU ran out of memory or had some memory issue...and has fallen back to continue rendering on CPU only.
          • The render times will increase drastically, as the CPU only processing is quite a bit slower than GPU accelerated.


          Things you can do:

          • You can confirm this is the case by looking at the log files. (%programdata%\SOLIDWORKS\SOLIDWORKS Visualize 2018\Log).  I think it's the SLDWORKSVisualize-iray.log.  Search for "out of memory" or similar.
          • Ensure you are not running Visualize main application, while the rendering is running.  If you are doing an offline render, while Visualize is also running, you essentially have 2 copies of the scene open...using twice the resources.
          • If you're not inclined to upgrade your GPU to get more memory, then you may have to workaround this by trying to significantly simplify the geometry (disabling any internal/non-visible components for example)
            • Re: Strange goings on in output rendering.
              Alexander Smith

              Hi Ron


              Thanks for your swift response.


              I will look into the log files tomorrow when I’m back at my desk. To be honest though I’d be surprised if it was running out of GPU power. The GPU I’m running is the 16gb NVIDIA Quadro P5000 card. And it’s not a complex scene at all.

                • Re: Strange goings on in output rendering.
                  Ron Bates

                  I'd be surprised too if you have a P5000 and a simple scene!


                  But it could be some other Optix error causing a different sort of issue that still triggers a fallback to CPU.  In which case, also search the logs for "cpu" and you may find an entry explicitly indicating it has fallen back to CPU.

                    • Re: Strange goings on in output rendering.
                      Alexander Smith

                      Hi Ron


                      I hope that you get a bit of time to relax after SWW and I hope it was a success.


                      So I looked through the log files and to be honest I have no idea at all what I am looking for so I gave up on that plan.


                      I also contacted the people that built my computer for me and asked them if there was anything they could do. They thought that it might have been a driver issue, that all rendering was being done through the CPU and onboard graphics and that it actually wasn't communicating at all with the P5000 card. So they completely uninstalled the GPU drivers from the GPU and the CPU (I think) and reinstalled the GPU driver for the P5000 only. I THINK its performing better, though not the rocket-ship increase in speed I was hoping for. They also recommended that I go into the Nvidia control panel and set the PhysX processor to the P5000 which is was not set to before hand.


                      Definitely though, as I watch the task manager while the queue is running the GPU is showing that it is running at 80-100% and the CPU is down to safer areas around 15%. However, having done a test render against one that I previously did before the driver update, the render  took the same time.... So now I'm befuddled!


                      Any advice? Perhaps I could share my screen with you on a call some time to show you what is happening and see if its all as it should be especially as I have no idea about those log files.

                        • Re: Strange goings on in output rendering.
                          Michael Dirisio

                          I'm running Dual NVIDIA P5000s, SLI (Dell didn't even offer that as an option last year when I asked for it.)


                          Be careful and make sure the drivers are supported by Solidworks & Visualize. The drivers that came installed on my machine were newer than what Solidworks supported at the time and it slowed down things considerably. After upgrading to 2018 things seem to be running better for me.


                          Typically I run in Hybrid, but this maxes out my GPU and CPU