I have a large collection of 12000 data entries for example and want to insert them via EF6 into a sqlite database. The most time consumes the instantiation of the data models:
at the moment I loop 12000 times 'new myItem()'
var myItem= new myItem
Id = result.Id,
Description = result.Description,
Property1 = result.Property1
The bottleneck is probably the adding of the entities to the context.
At first it doesn't take much time, but after 100s or 1000 records, it does.
See also this answer for other optimizations you might be able to add (read the comments of the linked answer!).