something like this- assuming there is a 1 to 1 relationship tblA.pKey = tblB.updateKey

UPDATE tblA

SET tblA.col1 = tblB.col1

FROM tblB

WHERE tblA.pKey IN (SELECT TOP (100) tblB.updateKey

WHERE ... update not applied condition ...)

OR

DECLARE @COUNT INT

SET @COUNT = 0

WHILE (@COUNT < 1500 )

BEGIN

WITH NumberedRows AS (

SELECT ROW_NUMBER() OVER(Order By tblB.updateKey) AS RN, *

FROM tblB )

UPDATE tblA

SET tblA.col1 = NumberedRows.col1

FROM NumberedRows

WHERE NumberedRows.RN BETWEEN ( @COUNT AND (@COUNT + 100) )

AND tblA.pKey = tblB.updateKey

SET @COUNT = @COUNT + 100;

END