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wallydb
Participant
November 15, 2017
Answered

GPU Rendering only uses CPU

  • November 15, 2017
  • 2 replies
  • 10075 views

When previewing 4K video on the timeline with some effects, it takes 11-17 seconds to show the preview for one frame. We have enabled the Ray-traced - GPU setting under Preview but the systems still uses 100% CPU and 1% GPU. As far as I read up in the forums, Ray-Trace is discontinued - so this setting is useless? Does this mean that only my CPU will be used when I work in AE for preview and (as I have read) also my GPU will only be used for rendering in certain situations where the effects and codecs used are compatible with GPU rendering.

System:

CPU: Intel(R) Core(TM) i7-6900K CPU @ 3.20GHz

GPU: NVIDIA GeForce GTX 1080​

Motherboard: X99P-SLI-CF

Memory: 64GB RAM

Adobe: After Effects cc 2018

This topic has been closed for replies.
Correct answer Rameez_Khan

Hi wallydb,

I think you're confused. There are two GPU settings.

We have enabled the Ray-traced - GPU setting under Preview but the systems still uses 100% CPU and 1% GPU. As far as I read up in the forums, Ray-Trace is discontinued - so this setting is useless?

The one that you seem to have enabled is for the old Ray-tracer (which is obsolete).

Does this mean that only my CPU will be used when I work in AE for preview and (as I have read) also my GPU will only be used for rendering in certain situations where the effects and codecs used are compatible with GPU rendering.

Another setting is under File > Project Settings > Video Rendering and Effects, which has to be set to Mercury GPU Acceleration. This is what controls whether things like GPU-accelerated effects and motion blur use the GPU for rendering and previewing. Please note that previewing and rendering (is complicated) use a mix of CPU and GPU depending on what features you're using. Don't be surprised if you notice the CPU being used more than the GPU or vice-versa.

Hope this information helps.

Rameez

2 replies

Rameez_Khan
Rameez_KhanCorrect answer
Legend
November 15, 2017

Hi wallydb,

I think you're confused. There are two GPU settings.

We have enabled the Ray-traced - GPU setting under Preview but the systems still uses 100% CPU and 1% GPU. As far as I read up in the forums, Ray-Trace is discontinued - so this setting is useless?

The one that you seem to have enabled is for the old Ray-tracer (which is obsolete).

Does this mean that only my CPU will be used when I work in AE for preview and (as I have read) also my GPU will only be used for rendering in certain situations where the effects and codecs used are compatible with GPU rendering.

Another setting is under File > Project Settings > Video Rendering and Effects, which has to be set to Mercury GPU Acceleration. This is what controls whether things like GPU-accelerated effects and motion blur use the GPU for rendering and previewing. Please note that previewing and rendering (is complicated) use a mix of CPU and GPU depending on what features you're using. Don't be surprised if you notice the CPU being used more than the GPU or vice-versa.

Hope this information helps.

Rameez

W
wallydbAuthor
Participant
November 16, 2017

Thanks Myleniumand RameezKhan,

My acceleration is enabled and set on the Mercury CPU Acceleration (CUDA) - still the system is not using my GPU. The card runs beautifully in programs like Blender and Mark3D.

    Szalam
    Community Expert
    SzalamCommunity Expert
    Community Expert
    November 16, 2017

    AE uses the GPU for very little. Other than the obsolete ray-traced renderer (which only used the GPU to create the 3d geometry - nothing else was accelerated), there are only a few effects that work on the GPU. I think the list is: Fractal Noise, Gaussian Blur, Fast Box Blur, Lumetri Color, Sharpen, Brightness and Contrast, Find Edges, Glow, Hue/Saturation, Invert, Tint, and (in some cases) the Transform effect. AE also (in some situations) uses the GPU to accelerate layer motion blur. Additionally, all the new VR effects require a GPU to render.

    However, the vast majority of effects and basic video file rendering don't use the GPU. (I think it uses the GPU to debayer R3D footage too, but I don't mess with RED cameras so I've not had to worry about it.)

      Mylenium
      Mylenium
      Legend
      November 15, 2017

      Does this mean that only my CPU will be used when I work in AE for preview and (as I have read) also my GPU will only be used for rendering in certain situations where the effects and codecs used are compatible with GPU rendering.

      Correct. It's all circumstantial and the usual limitations apply - a single CPU-only effect will still break GPU rendering as will several other conditions inherent to how AE works.

      Mylenium

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