# vtkVortexCore is running very slow
**URL:** https://discourse.vtk.org/t/vtkvortexcore-is-running-very-slow/8242
**Category:** Support
**Created:** [April 9, 2022, 9:07am UTC](https://discourse.vtk.org/t/vtkvortexcore-is-running-very-slow/8242 "2022-04-09T09:07:28Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@adeelz92](https://discourse.vtk.org/u/adeelz92)
#### Post date: [April 9, 2022, 9:07am UTC](https://discourse.vtk.org/t/vtkvortexcore-is-running-very-slow/8242/1 "2022-04-09T09:07:28Z")
vtkVortexCore in C++ is running very very slow . It takes around 30 minuntes to get the results. The same code works fine in vtk-python installed with pip. The version for both python and C++ is same, 9.1.
```auto
vtkNew vortexCore;
vortexCore->SetInputArrayToProcess(0, 0, 0, vtkDataObject::FIELD_ASSOCIATION_POINTS, "velocity");
vortexCore->SetInputData(reader->GetOutput());
vortexCore->Update();
```
**Enivronment**
Windows: 8.1
Build Tool: Visual Studio 2017
I used default options to build vtk using cmake and visual studio 2017. Any suggestion would be appreciated.
---
### Author:  [@Francois\_Mazen](https://discourse.vtk.org/u/Francois_Mazen)
#### Post date: [April 11, 2022, 6:59am UTC](https://discourse.vtk.org/t/vtkvortexcore-is-running-very-slow/8242/2 "2022-04-11T06:59:11Z")
Hello @adeelz92
You should check that the CMake variable `VTK_SMP_IMPLEMENTATION_TYPE` is set to `tbb` or `openmp` to enable multithread computation.
Best,
---
### Author:  [@adeelz92](https://discourse.vtk.org/u/adeelz92)
#### Post date: [April 11, 2022, 8:34am UTC](https://discourse.vtk.org/t/vtkvortexcore-is-running-very-slow/8242/4 "2022-04-11T08:34:52Z")
I tried changing the variable to `openmp` and built again but no difference.