It is nothing short of a colossal disaster to use GUID for primary key as opposed to IDENTITY (int, 1,1) function.
The INT IDENTITY is 4 bytes and sequential when new rows are inserted.
GUID is 16 bytes (larger index tree) and RANDOM for new row insertion. That means quickly trashes the index tree.
For testing, just test for index fragmentation after certain number of inserts which would be typical in your environment.
Kalman Toth - Database, Data Warehouse & Business Intelligence Architect
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