slow result

Hi,

I have a slow response of my PostgreSQL database 7.4 using this query below
on a table with 800000 rows:

select count(*)from tbl;

PostgreSQL return result in 28 sec every time.
although MS-SQL return result in 0.02 sec every time.

My server is a DELL PowerEdge 2600 with bi-processor Xeon at 3.2 Ghz
with 3GBytes RAM

My PostgreSQL Conf is
*********************
log_connections = yes
syslog = 2
effective_cache_size = 50000
sort_mem = 10000
max_connections = 200
shared_buffers = 3000
vacuum_mem = 32000
wal_buffers = 8
max_fsm_pages = 2000
max_fsm_relations = 100

Can you tell me is there a way to enhence performance ?

Thank you

+-----------------------------------------------------+
| Laurent Manchon |
| Email: lmanchon(at)univ-montp2(dot)fr |
+-----------------------------------------------------+