Fortnite stutters heavily and has below expected performance on DirectX 12.

Sometimes the Fortnite client will try to repeatedly recompile DirectX shaders without stopping, which results in heavy stuttering while playing on DirectX 12 rendering mode. Clearing the shader cache can potentially fix this issue. Follow the steps below in order to do so:

1. Make sure Epic Games Launcher and Fortnite are closed.
2. Press the Windows key + R combination, and a run window will open.
3. In the text field type %appdata% and hit enter.
   
4. The Roaming folder will open.
5. Using the up arrow next to the folder path, navigate to the AppData Folder
   
6. Open LocalLow folder
7. Follow the next steps based on what graphic card you have:
   • For NVidia graphic card users:
     1. Open the NVIDIA folder
     2. Open the PerDriverVersion folder
     3. Open the DXCache folder
     4. Select all files in DXCache folder, right click them and choose delete.
     5. If some files cannot be deleted due to being in use, choose to ignore it.
     6. Using the same up arrow to navigate, go back to AppData folder
     7. Once in the App Data folder, open the Local folder
     8. Open the NVIDIA folder
     9. Open the PerDriverVersion folder
     10. Open the DXCache folder
     11. Select all files in DXCache folder, right click them and choose delete.
     12. Using the same up arrow to navigate, go back to the NVIDIA folder
     13. If there is a DXCache folder located in it open it
     14. Select all the files within that folder, right click and choose delete.
     15. Choose ignore for the files that cannot be removed due to being in use
   • For AMD graphic card users:
     1. Open the AMD folder
     2. Open the DxCache folder
     3. Select all files in the DxCache folder, right click them and choose delete.
     4. If some files cannot be deleted due to being in use, choose to ignore it.
     5. Using the same up arrow to navigate. go back to AppData folder
     6. Open the Local folder
     7. Open the AMD folder
     8. Open the DxCache folder
     9. Select all the files in the DxCache folder, right click them and choose delete.
     10. Choose ignore for the files that cannot be removed due to being in use
8. Launch Fortnite and play a match. Your first match may still be stuttery, this is due to game client compiling new shaders.
9. If there's no difference, close the game and repeat the steps from point 6, launch the game again and test.