I have an unusual problem. I render a frame and it takes 1:46. Seven frames later it takes 2:18 to render a frame. Fifteen frames later it takes 2:34. After a few hours of rendering it takes over 5 minutes to render a frame. I am using Blender 2.79b with an Acer Predator G1-710 Intel i7-7700 3.6 GHz Nvidia GeForce GTX 1080 and Windows 10 64 bit. My animation is about 17,000 frames long and I use hair and particles and transparencies. I have set Cycles render using the GPU. I am rendering single layers. The workaround is for me to close Blender, re-open it and continue rendering where I left off. The render time for the next frame is then 1:56. I do not have this problem rendering the same file on my Mac nor on my old PC. So, does anyone have any ideas as to how I can achieve a relatively consistent render time for each frame?

  • $\begingroup$ Your system might be overheating. To check this, download a software like gpuz and watch the sensors of your GPU for several minutes. $\endgroup$
    – yann
    Mar 29, 2018 at 8:31
  • $\begingroup$ thanks for the tip yann...I ran GPU-Z and made a log file...after 12 hours the temp of the GPU is stable, well within the range of the card. I've noticed that the bulk of the time is not spent on rendering a frame but rather on Synchronizing Objects, Building BVH and Packing BVH nodes. $\endgroup$
    – TDolle
    Mar 30, 2018 at 6:15
  • $\begingroup$ I've found a solution for a similar scenario: blender.stackexchange.com/questions/111681/… $\endgroup$
    – alterdings
    Jun 28, 2018 at 12:31


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