http://pastebin.ca/57220

Regarding:

>shared_buffers = 6400 # Was twice this, dropped it because the system was swapping
>work_mem = 3120 # Was 5 megs, dropped it because the system was swapping

Start thinking about upgrade of RAM size and increment size of shared_buffers to, if possible, size of main tables in DB.

>commit_delay = 60000
>commit_siblings = 2
More useful split XLOG on separate disk for avoid heads motion (delay) during modify tables