Performing a spatial join with a large amount of features when using the spatial join from the layer context menu > Joins/Relates > Join > Join Data dialog box results in a crash.
The Spatial Join tool from the Join Data dialog box performs best when using datasets that are less than 20,000 features. Under these conditions, it is highly unlikely for a memory error to occur with any modern PC.
There is a documented case where several hundred thousand features are being spatially joined to another dataset that also consists of several hundred thousand features.
On older PCs, and some modern PCs, the spatial join does not complete due to memory error, and results in a crash. The design of this tool was optimized for small datasets, that is < 20,000 features, and is still capable of performing with over 200,000 features, dependent on the number of Target and Source features.