VACUUM FULL ANALYZE on 8.1.4 is slower then on 8.0

Hello!

After upgrade PostgreSQL from 8.0 to 8.1.4 a VACUUM FULL ANALYZE
process is much slower, from logs:

8.0
[13666][postgres][2006-10-06 01:13:38 CEST][1340121452] LOG:  statement: VACUUM FULL ANALYZE;
[13666][postgres][2006-10-06 01:39:15 CEST][0] LOG:  duration: 1536862.425 ms


8.1
[4535][postgres][2006-10-10 01:08:51 CEST][6144112] LOG:  statement: VACUUM FULL ANALYZE;
[4535][postgres][2006-10-10 02:04:23 CEST][0] LOG:  duration: 3332128.332 ms

Databases are equal.
I'm not using autovacuum.

Linux kernel is the same in two cases.
$uname -a
Linux zamczysko 2.6.13.4 #2 SMP Tue Oct 18 21:19:23 UTC 2005 x86_64 Dual_Core_AMD_Opteron(tm)_Processor_875 unknown PLD
Linux

Why new PostgreSQL is slower?

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Andrzej Zawadzki