performance penalty of strings as primary keys?

Question

What would be the performance penalty of using strings as primary keys instead of bigints etc.? String comparison is much more expensive than integer comparison, but on the

Answer 1

In our product we use varchar(32) for primary keys (GUIDs) and we haven't met performance issues of this. Our product is a web site with extreme overload and is critical to be stable. We use SQL Server 2005.

Edit: In our biggest tables we have more than 3 000 000 records with lots of inserts and selects from them. I think in general, the benefit of migrating to int key will be very low, but the problems while migrating very high.