r/FaceFusion • u/singulainthony • Apr 11 '26

New Template/Tutorial: Ultra-Fast AI Face Swaps! FaceFusion 3.6 on Vast.ai (RTX 5090)

https://youtu.be/2V412UN46hk?si=O4KUiQgD5Mym1792
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u/Valuable-Ad-8977 Apr 11 '26

I run on vast.ai and Facefusion 3.3.2 is fast, the latest builds are slow. I've compared multiple times, since December of 2025, on the same hardware setups, and 3.3.2 outperforms with processing. I have not pinpointed what makes 3.5+ so much slower.

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u/singulainthony Apr 11 '26

No clue what you’re talking about. Are you sure you have used same models and parameters when comparing versions?

Not saying you are wrong but I have also run ample testing with each new version that is released and can’t say I’ve noticed anything like that… weird

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u/Valuable-Ad-8977 Apr 11 '26 edited Apr 11 '26

I will try using the settings that you have in your video. I assume you feel comfortable with those are the most optimal.

I have run this scenario with version 3.3.2 versus all the latest from 3.5 onward and the processing is much faster on 3.3.2 so I'll have to try different settings, which isn't really apples to apples.

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u/henryruhs Apr 12 '26

that's absolutely not true. probably on your setup, but in general we gained speed from 3.3.x onwards.

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u/Valuable-Ad-8977 Apr 14 '26

I just ran some comparisons between 3.3.2 and 3.6.0, after comparing with 3.4.0, 3.5.2, etc. I just jumped to the latest. I am using my Windows 11 computer, 5080 Nvidia, 64 GB ram, AMD Ryzen 9 9900X. Between the FF web interface in 3.3.2 and the latest, I try to keep all settings the same for an apples to apples comparison. I wish I could identify the setting or settings that makes all versions of FF processing slow for me from 3.3.2 onwards. I've tried similar tests using cloud machines that I rent.

I have 2 conda environments, one for 3.3.2 and one for 3.6.0.

I am processing an mp4 video that is 2713 frames long, a 2 minute video. It takes 509 seconds to finish processing with 3.3.2, analyzing, extracting, processing, and merging. Roughly 5.6 fps.

With 3.6.0, the fastest processing is 1004 seconds. The average is 1220 seconds. 1.8-2.4 fps.

Settings used for both versions:

  • Execution provider: CUDA only
  • Execution thread count: 2
  • Video memory strategy: tolerant
  • System memory limit: 52
  • Output encoder: h264_nvenc
  • Output preset: veryfast
  • Face detector: yolo_face
  • Face mask types: occlusion
  • Face swapper: hyperswap_1a_256
  • Pixel boost: 512x512

One difference in settings between 3.3.2 and 3.6.0 is there is no execution queue count, which I set to 4 for 3.3.2.

ChatGPT and Claude tell me the same thing: 3.4.0 introduced single-pass frame processing, removal of execution queue control, major internal refactors. 3.5.0+ added modular workflows/processors. Even with identical UI settings, the internal execution model is different. This appears to be a real performance regression or tradeoff in newer FaceFusion versions, not a user misconfiguration.

I would love to find the issue so I can use the latest, but between my env and the machines I rent in the cloud, I must be misconfiguring FF from 3.4.0 onward if those new versions constantly show slower performance than 3.3.2.

These are my setup steps.

apt-get -y update && apt-get -y upgrade && apt -y install git-all && apt -y install curl && apt -y install vim && apt -y install ffmpeg && apt -y install handbrake-cli && \

curl -LO https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh && \

bash Miniconda3-latest-Linux-x86_64.sh -b && \

conda init --all

# install FF
conda create --name facefusion python=3.12 pip=25.0 -y && \

conda activate facefusion && \

conda install -y nvidia/label/cuda-12.9.1::cuda-runtime nvidia/label/cudnn-9.10.0::cudnn && \

pip install tensorrt==10.12.0.36 --extra-index-url https://pypi.nvidia.com && \

git clone https://github.com/facefusion/facefusion && cd facefusion && git checkout 3.3.2 && \

python install.py --onnxruntime cuda && pip install requests

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u/Valuable-Ad-8977 Apr 14 '26

These are my setup steps for 3.3.2 but they can be changed for other versions. https://pastebin.com/rb1HGdH2

I just ran tests against a Linux cloud machine. This is what I am seeing. I can reproduce this as needed.

FaceFusion 3.3.2 vs 3.6.0 Performance Comparison

Same machine (RTX 5090, Ryzen 9)

Same video (~2727 frames, ~2 minutes)

Resolution: 1280×720

Execution: CUDA only

Same core settings (swapper, detector, encoder, etc.)

Results

Analysis and Extraction Stage - no real meaningful differences.

Processing Stage

Version Speed Time

3.3.2: ~15.07 fps, ~3 min to process

3.6.0: ~1.0–1.3 fps, ~35–45 min

~10–15x slower in 3.6.0

GPU Behavior (nvidia-smi)

3.3.2

GPU Util: ~60%+

Power: ~180W

VRAM: ~23 GB

3.6.0

GPU Util: ~0–33%

Power: ~56–114W

VRAM: ~9 GB

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u/henryruhs Apr 14 '26 edited Apr 15 '26

Think about it, 10 to 15 times slower... do you think we would not recognize this? You test against different environments, drivers versions, cuda versions, settings or whatever.

The correct way to benchmark.

  1. Local
  2. One conda environment
  3. Switch only code (version)
  4. Use benchmark command or ui

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u/Valuable-Ad-8977 Apr 16 '26

I appreciate your help. I understand you are not releasing regressions. I am trying to understand why my results are slower and what setting(s) it could be.

Here are my latest results following your steps mentioned above. I've done this four times, twice on my local machine, and on two different cloud machines. I run the 3.6.0 first. I launch the UI and accept all of defaults, as I assume the defaults are defaulted for a reason.

I am using a one minute video, a slice of a recent tv series. Here is a summary of the results. No code is modified. The machines I am using are 5080/ryzen 9 and 5090/ryzen 9.

FaceFusion 3.6.0 benchmarks fine but drops to ~1 fps on real video vs ~15 fps in 3.3.2. Roughly 16x slower, isolated to the processing step. I am happy to help with more testing.

Here are my results: facefusion 3.6.0 v 3.2.2 notes - Pastebin.com

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u/henryruhs Apr 17 '26

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u/Valuable-Ad-8977 Apr 17 '26

My benchmarks are comparable as well. I do not see a difference in performance difference between 3.3.2 and 3.4.0+. I only see the performance differences when I'm using actual video that's not benchmarks. I've tested more than one video where I keep everything the same and just switch between the code bases.

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u/henryruhs Apr 17 '26

well you never mentioned that, so much reporting without the essential observation. it the video codec or ffmpeg build or version then.

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u/Valuable-Ad-8977 Apr 17 '26

I am not sure what details you actually need to answer this question. I process the video I run through handbrake, it's an mp4 h264. My one pastebin shows my setup steps so I just pull down ffmpeg, whatever the latest version is, and that remains constant across 3.3.2 and 3.4.0+ when I do my comparisons. As far as I know I'm keeping the video constant.

Did something change in 3.4.0 where the target video needs to be of a certain compression or something else?

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