I moved all my users to the Evo view and got everyone off the Classic all users are on the same page as far as what they are doing--makes troubleshooting much easier!
We don't really have much issues with lag, only on the tables where there are a ton of records and I am not allowed to archive records from them. Archiving has a great way of speeding things up and the records are still accessible.
Where we have archived the lookups for those tables are lickety-split fast.
FWIW
Val