speed Postgresql 7.0 vs PostgreSQL 6.5.2

        Hie ,

    I've just install PostgreSQL 7.0.2 on i686-pc-linux-gnu      (Pentium 233 with
64 Mo RAM)
     But i've also PostgreSQL 6.5.2     "
"     (P              450  with 256 Mo RAM)
    I've dump one of my big database (500000 rows) on the new one .

    I've made some test and one of my querie take      7 sec on the old server

1 sec on the new
    The EXPLAIN seem to be different .
    Is it a improvement or a mistake ?

    With this good result  , Postgresql 7.0 equals Mysql  ! I'll be very happy , if
you confirm that PostgreSQL have such improve the speed ...



This is the request :

    SELECT DISTINCT n.username from newlog2000 n , realms r where ( (n.username
like 'loic@%' ) and (r.host = 'toto.fr' ) and (
substr(n.username,strpos(n.username,'@')+1) = r.domain ) ) ;


NOTICE:  QUERY PLAN: (on the new server PostgreSQL 7.0    200 Mhz  64 Mo RAM )

Unique  (cost=253.85..254.07 rows=9 width=24)
  ->  Sort  (cost=253.85..253.85 rows=91 width=24)
        ->  Nested Loop  (cost=0.00..250.90 rows=91 width=24)
              ->  Seq Scan on realms r  (cost=0.00..22.50 rows=10 width=12)
              ->  Index Scan using newuser2000 on newlog2000 n  (cost=0.00..4.74
rows=905 width=12)

NOTICE:  QUERY PLAN: (on the old server PostgreSQL 6.5   450 Mhz   256 Mo RAM)

Unique  (cost=14107.55 rows=7897 width=24)
  ->  Sort  (cost=14107.55 rows=7897 width=24)
        ->  Nested Loop  (cost=14107.55 rows=7897 width=24)
              ->  Index Scan using newuser2000 on newlog2000 n  (cost=9773.30
rows=658 width=12)
              ->  Seq Scan on realms r  (cost=6.59 rows=120 width=12)



                                        Thanks for all , and sorry for my english
....


loic