Slow running to_tsvector (tsearch2 in PG 8.2.3)

[Henrik Zagerholm <henke(at)mac(dot)se>]

Hello list,

I've been testing tsearch2 for a while and I recently noticed some  
really slow queries.

This is a quite big document so the times are maybe accurate.

The document has about 194 000 words.

I put all the data in tbl_fulltext.fulltext_text and then did a

update tbl_fulltext set vectors = to_tsvector(fulltext_text);

Which takes about 80 seconds to complete.
The hardware is a Pentium 4 2.8GHz with 1GB HyperX memory.

Is this normal? What can I tweak in postgresql.conf to speed up big  
to_tsvector()?

Regards,
Henrik