PostgreSQL Strange Timings

A very simple query. PostgreSQL 8.4. I have no idea why the simple query is 7 times faster than the EXPLAIN ANALYZE version. Any ideas? Anyone?

test_counters=# SELECT COUNT(*), xtype FROM test GROUP BY xtype ORDER BY xtype;
  count  | xtype
---------+-------
  669000 | A
   84000 | B
   63000 | D
   15000 | E
  159000 | G
 7866000 | H
 1000000 | N
  144000 | NI
(8 rows)

Time: 3366,822 ms
test_counters=# explain analyze SELECT COUNT(*), xtype FROM test GROUP BY xtype ORDER BY xtype;
                                                           QUERY PLAN
---------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=243136.22..243136.24 rows=8 width=2) (actual time=24544.883..24544.889 rows=8 loops=1)
   Sort Key: xtype
   Sort Method:  quicksort  Memory: 25kB
   ->  HashAggregate  (cost=243136.00..243136.10 rows=8 width=2) (actual time=24544.838..24544.848 rows=8 loops=1)
         ->  Seq Scan on test  (cost=0.00..193136.00 rows=10000000 width=2) (actual time=0.012..11501.738 rows=10000000 loops=1)
 Total runtime: 24544.980 ms
(6 rows)

Edition:
It turned out that there is a problem with the gettimeofday() function as Tom Lane wrote:

You’ve got a machine where gettimeofday() is really slow. This is common on cheap PC hardware

http://archives.postgresql.org/pgsql-general/2010-03/msg00770.php

And I really have no idea what to do.

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