When using a grid against a large table with server side filtering (ToDataSourceResult) ToDataSourceResult builds a SQL query that converts the search string to UPPER() and therefore prevents the database from using its indexes. As SQL comparison is case insensitive that LOWER() is unnecessary. As we have may grids where this is an issue it would be time consuming to build out manual filters for each grid instead of using ToDataSourceResult This was discussed here and there was no solution at the time: https://www.telerik.com/forums/grid-filtering-on-text-using-lower-in-sql I would liek to request an option to tell ToDataSourceResult() not to use LOWER() in the sql? See ticket #1339310