Adding names to list takes a long time

Question

I have a list with about 5000 names.  I ran a query to find people that should be added to this large list but haven't yet.  I got 1600 names of with 200 had not already been added.  Does it make sense that it should take over 4 minutes to add those 200 names?  Is something not running correctly?

Answer 1

Lists are meant for much smaller groups of people. Over a thousand names it will be much faster by adding a flag.