Is there a better way to represent this WHERE clause so is does not use the Non-SARGable funtion ISNULL?

    1=1
    AND ISNULL([TABLE_NAME_1].[FIELD_NAME_1], -1) <> ISNULL([TABLE_NAME_2].[FIELD_NAME_1], -1)
     OR ISNULL([TABLE_NAME_1].[FIELD_NAME_2], -1) <> ISNULL([TABLE_NAME_2].[FIELD_NAME_2], -1)

This is an update statement which compares table 1 to table 2 and only updated where there is a difference

TABLE 1 represents a working table which is updated daily
TABLE 2 represents a final table which users report against