# Speed up ITK Registration Pipeline
**URL:** https://discourse.itk.org/t/speed-up-itk-registration-pipeline/3941
**Category:** Algorithms
**Created:** [March 8, 2021, 8:51pm UTC](https://discourse.itk.org/t/speed-up-itk-registration-pipeline/3941 "2021-03-08T20:51:12Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@PauloFavero](https://discourse.itk.org/u/PauloFavero)
#### Post date: [March 8, 2021, 8:51pm UTC](https://discourse.itk.org/t/speed-up-itk-registration-pipeline/3941/1 "2021-03-08T20:51:12Z")
Hello Everyone,
I implemented a registration pipeline using MattesMutualInformation as the metric algorithm.
I am reaching convergence around 50 iterations but these iterations are taking nearly 4 minutes. My computer has an i7-9750, 16GB RAM, and an Nvidia RTX 2060 6GB.
I tried setting up the WorkUnits but no improvement was noticed. I looked into some questions on the forum regarding the GPU implementation and, as far as I understood, there isn’t a current implementation of the registration framework on the GPU.
The moving image is 640x402 and the fixed image is 640x480. Is processing time normal? Is there a way in which I can use the GPU or use more threads?
Thanks
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### Author:  [@dzenanz](https://discourse.itk.org/u/dzenanz)
#### Post date: [March 8, 2021, 9:45pm UTC](https://discourse.itk.org/t/speed-up-itk-registration-pipeline/3941/2 "2021-03-08T21:45:10Z")
If that is a 2D image, registration should be done in seconds. Debug can be 100x slower than release.
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### Author:  [@pip010](https://discourse.itk.org/u/pip010)
#### Post date: [March 9, 2021, 12:52pm UTC](https://discourse.itk.org/t/speed-up-itk-registration-pipeline/3941/3 "2021-03-09T12:52:58Z")
MattesMutualInformation really works different than the rest and in fact does not fit conceptually the ITK framework, the transformation is non-linear so the cost per iteration is higher than the rest of the co-reg algorithms. Several things you can try: (1) relax the criteria for convergence (2) do provide better initial transform. Also, as @dzenanz suggested try not to use debug but instead use release with debug symbols.
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### Author:  [@PauloFavero](https://discourse.itk.org/u/PauloFavero)
#### Post date: [March 9, 2021, 1:54pm UTC](https://discourse.itk.org/t/speed-up-itk-registration-pipeline/3941/4 "2021-03-09T13:54:37Z")
Thanks everyone.
I was sure to be running on release mode. Later on, I found an error on my CMake file that was making it to always build on debug.
Now, the registration task is running on 2 seconds 🙂