create table #Tmp(n int not null primary key)
insert into #Tmp values(0)

declare @k int = 1

while @k < 1024 * 1024 * 32
begin
	insert into #Tmp
	select n + @k
	from #Tmp

	select @k = @k + @k
end

declare @dummy bigint

declare @d1 datetime = GetDate()

select
	@dummy = Sum(Convert(bigint, n))
from
	#Tmp

declare @d2 datetime = GetDate()

select
	@dummy = Sum(convert(bigint, n0))
from
	(
	select
		n0 = Lag(n) over (order by n)
	from
		#Tmp
	) as Q

declare @d3 datetime = GetDate()

select Convert(time(3), @d2 - @d1), Convert(time(3), @d3 - @d2)
-- 00:00:01.460, 00:00:46.273

drop table #Tmp