Outrageously Slow Render Times with Cycles

Hi All,

I’m very new to Blender (working with most updated version 2.78) and am finally getting to the point where I can render out some animations. I’m currently trying to render a 130 frame animation of a simple scene (taken from blendswap: https://www.blendswap.com/blends/view/78302) and am having to wait over 23 minutes per frame to render. That’s over 2 days for a 5 second animation – that’s crazy!

I am operating on a 2013 Mac Pro (https://www.apple.com/mac-pro/), which has Dual AMD FirePro D300 graphics cards. I haven’t updated to OS X Sierra yet, and am still operating on OS X Yosemite Version 10.10.5 (which could be part of the problem).

My first issue is that I have to render on CPU. When I tried to use GPU, however, it wasn’t working at all at first. Now it seems to be working at least, but is actually going even SLOWER than the CPU – 1 frame is rendering at 33 MINUTES! With results like that, I’m sticking with CPU. I’ve read multiple times that there has always been issues with AMD and Cycles and that Nvidia is better, however these were older articles and I was under the impression that AMD should now be supported in 2017 and Blender 2.78. I tried to look on AMD’s website to see if I could update the FirePro drivers, but found no driver downloads for Apple computers.

In a nutshell, I’m aware I could improve my render times with a better graphics card, but unfortunately I am not in a position where I can upgrade right now. What I’m looking for is a way to get the most out of what I currently have, and on a $3,000 machine I would hope that performance could be better than 2 days for 5 seconds of animation…

First I’ll start with render settings. I’ve watched numerous tutorials on rendering (blenderguru etc) so I don’t think I’m doing anything too crazy to cause rendering to be so slow.

In summary:

I’m rendering 1920x1080 100%, 24fps.
Output to PNG with 15% compression - RGB - Color Depth set to 8.
Samples are set to 600 (square samples is not selected).
Animated seed is turned on.
I was getting fireflies so I set clamp direct + clamp indirect to 5.00 each, and turned off reflective + refractive caustics, and have filter glossy set to 0.50 (as noted in this blender guru article.)
For tiles, I have it set to Hilbert Spiral. When rendering with CPU: x= 16 y = 16. When rendering with GPU: x = 256 y = 256.

I’m aware I can lower the samples too to cut down the render time a bit but I found 600 was giving me the quality image I want and seemed pretty normal.

Here are screenshots of my settings in case I am missing something (all settings other than tiles remained the same for CPU rendering):

As far as everything else goes, I’ve added two lights 1 point and 1 hemi. Here are their settings:


  • Max bounces: 1024
  • Cast Shadow and Multiple Importance checked
  • Strength: 10.000


  • Size: 2.33m
  • Max bounces: 1024
  • Cast Shadow and Multiple Importance checked
  • Strength: 1000.000

Are my lights making this take forever?

The only other thing I can think of is this: I am using Filmic Blender for my color management (https://github.com/sobotka/filmic-blender). Here are my settings:

Display Device: sRGB/BT.709
View: Filmic Log Encoding Base
Look: Base Contrast
Color Space: sRGB EOTF

I am desperately trying to figure out and understand what it is I’m doing wrong because I’m in utter disbelief that it just actually takes this long to render. 15 minutes per frame? Acceptable. 33 minutes per frame? Absolutely crazy, especially for something simple like this.

I will greatly appreciate any help/ information. Thank you in advance!!

Welcome to CGI! Most people are shocked at how long it takes to render a single frame. 23 minutes is actually on the lower end. You can do some optimization and get away with less samples using denoising (still beta), but it’ll still take a long time to render an animation. Whether a scene is simple or not doesn’t necessarily make a difference.

You can also rent out lots of computers via services like render.st or (if you have the knowledge) Amazon EC2.

I’m not sure if the problems with OpenCL are ironed out yet (especially on the Mac), but for best performance you must use larger tile sizes than on the CPU.

What’s crazy is your post. Probably took a long time to write, making it too long to read. Most of the information could’ve been shared by uploading a .blend without writing anything, except the ones only you have or specifically want to point out. The file gives a quick access for testing, but also is the source for screenshots when answering.

You’re using cropshots with the same information you’ve written, and no other feedback from the interface obviously. Uppercasing normal words doesn’t make your text clearer or easier to read, especially with the acronyms. You used paragraphs, which does help reading and replying.

Yes it could be a problem with Blender and your hardware or operating system, testing the file on other systems might help to figure that one out. But long render times with animations is not unheard of, it’s what you’re asking from the renderer and what you render with

And maybe the scene you’re rendering isn’t that simple. Transmission rays for transparency/translucency/refraction take more bounces and samples to clear, and highly reflective surfaces don’t help either.

Thanks BeerBaron!

I knew rendering animations was a long, painful process. What freaks me out is that we’ve rendered a more complex scene at the office on an older computer in Cinema 4d that was the same length in half the time (1 day instead of 2 lol).

There’s a lot that drove me to use Blender instead of Cinema 4d, I just really hope I can improve render time at least a little bit.

Thanks again for the info. I’ve contacted AMD to see if there’s anything I can do. I will update this thread with their response.

Lol JA12,

No need to take it so seriously! Wanted to give background info on computer/OS and what I already knew, so people would have a better idea of where I was coming from.

Mainly looking for people who have experienced rendering with Cycles on the same computer set up as mine, which is why I focused more on that than the .blend file. Not really concerned about this scene in particular, more concerned about enhancing Cycles rendering on Mac Pro AMD FirePro D300 in general. This scene is an example among other slow attempts I’ve experienced.

Believe me, I’m aware it takes a long time to render 3d. As stated in another response, I have experienced faster render times on the Mac Pro with Cinema 4d over here, but I prefer Blender over Cinema 4d so I’m looking for any possible solutions to using Blender with this computer.

Thanks for the info and taking the time to respond though!

C4D on CPU is faster than Cycles on CPU, but Cycles on GPU is faster than C4D, although I can only speak for CUDA. Is perhaps AMD OpenCL slow?

Are you using small tile size for CPU, right? (16x16)

I take this scene to test last Denoiser. Default scene, but 1080 size, only 200 samples. Denoising enabled with values by default, except Feature strength=0.6. CPU i7 3770:


I’m not sure that with this setting then visible patches appear in animation. You may have to use a more reasonable high sample value for animation.

diffuse bounces are a killer. 2 should be plenty. dont clamp direct, only indirect, since thats where fireflies happen. personally, i keep the min same as max.

arent firepro like nvidias quadros? if so, those cards generally arent optimized for single precision.

fun fact: hemi is same as sun in cycles. (unless this changed?).

i dont like multiple importance on my lamps, i feel its more noisy.

Cinema 4D’s renderer is not a “modern” path tracer like Cycles, so it won’t be quite as expensive to render with it on modern hardware. Of course, long render time is the #1 argument against a path tracer, but it’s also kind of the only argument. Path tracing is “the future”, all the big guys have switched to it. Too bad not everybody has a computer from the future, too.

Thanks everyone for taking the time to respond!

With some of the suggestions, I ended up getting my render time down to around 16-17 mins/frame, without degrading the quality of the image much at all. I ended up finding 400 samples was enough, changed clamp direct to 0 and clamp indirect to 2, and changed tile size for CPU rendering from 16x16 to 8x8. I also turned off glossy ray visibility.

Still haven’t heard anything from AMD customer support, but once I do I will post information here.

I may be a little late responding but: Just make sure you try out the denoiser; you can cut your render times in half or more!

The denoiser is still in beta, as BeerBaron said but it’s definitely worth the effort. In addition, the denoiser should be able to remove your fireflies so you won’t need the ridiculously low clamp value of 2 (that can seriously harm your dynamic range). Be sure also to set to static noise seed so that the low frequency noise that currently affect the denoised images doesn’t ruin your animation.