Sql em 3 tabelas muito lento

SELECT a.Ordem, a.Artigo, a.dtInicial, a.dtFinal, a.Turno, b.SubSetor
 
FROM tblCorteOrdem AS a LEFT JOIN tblCorteModeloComponentes As b ON a.Artigo = b.Artigo
 
WHERE NOT exists (
 select * from 
 (SELECT distinct Ordem FROM tblCorteOrdemSubSetor) c where c.ordem=a.ordem )
 
 
 GROUP BY a.Ordem, a.Artigo, a.dtInicial, a.dtFinal, a.Turno, b.SubSetor
 
ORDER BY a.Ordem

SELECT
	a.Ordem, a.Artigo, a.dtInicial, a.dtFinal, a.Turno, b.SubSetor
FROM
	tblCorteOrdem AS a
LEFT JOIN
	tblCorteModeloComponentes AS b ON b.Artigo = a.Artigo
LEFT JOIN
	tblCorteOrdemSubSetor AS c ON c.Ordem = a.Ordem
WHERE
	c.Ordem is null
GROUP BY
	a.Ordem, a.Artigo, a.dtInicial, a.dtFinal, a.Turno, b.SubSetor
ORDER BY
	a.Ordem

SELECT a.Ordem, a.Artigo, a.dtInicial, a.dtFinal, a.Turno, b.SubSetor

FROM (tblCorteOrdem AS a

LEFT JOIN tblCorteModeloComponentes AS b ON a.Artigo = b.Artigo )

LEFT JOIN tblCorteOrdemSubSetor AS c ON c.Ordem = a.Ordem

WHERE IsNull(c.Ordem)

GROUP BY a.Ordem, a.Artigo, a.dtInicial, a.dtFinal, a.Turno, b.SubSetor

ORDER BY a.Ordem