jg, 20.03.2013 12:13:
> I suspect the heavy fragmented files to the cause of the IO wait
> grows (PostgreSQL on WIndows).
>
>How to cope with that?
I would first investigate that it's *really* the fragmentation.
As a database does a lot of random IO, fragmentation isn't such a big issue.
You could use e.g. contig[1] from SysInternals to de-fragment the data files and then check if that really improves performance.
Thomas
[1] http://technet.microsoft.com/de-de/sysinternals/bb897428