Geoprocessing in QGIS can be very time consuming and computer demanding. Upon the raster extension some spatial analysis are not feasible and sometimes produces high amount of unuseful output data. Actually QGIS or any other GIS software can prevent you to send demanding requirements, so it is up to the user to consider cropping the raster to a specific area of study in order to optimize the process.
This tutorial show the procedure to cut a NDVI Raster File calculated from a Sentinel 2 Granule on QGIS.
This post is a part of a group of videos called "Working with Sentinel 2 Imagery on QGIS" that shows the complete procedure to download, represent and process Sentinel 2 images in QGIS, more information in this link: