Why does performance increase when moving from a derived table to a temp table solution?

Question

Why does performance increase when moving from a derived table to a temp table solution?

I read "Distributing SQL Server Execution Plans" from Grant Fritchey, and it helps me find out a lot why some queries are slow.

However, I am at a standstill with this case where a simple rewriting process is much faster.

This is my first attempt, and it takes 21 seconds. It uses a view:

-- 21 secs
SELECT *
  FROM Table1 AS o JOIN( 
    SELECT col1
    FROM    Table1
    GROUP BY    col1
    HAVING  COUNT( * ) > 1
) AS i ON ON i.col1= o.col1

My second attempt is 3 times faster and just moves the view to the temporary table. Now it is 3 times faster:

-- 7 secs
SELECT col1
INTO    #doubles
FROM    Table1
GROUP BY    col1
HAVING  COUNT( * ) > 1

SELECT *
FROM Table1 AS o JOIN #doubles AS i ON i.col1= o.col1