[buffers]
lazy_delay=20
The number of milliseconds the database manager waits for requests from applications before it begins to write to disk cached information almost due to be lost out from the cache. Because writing to disk may be a slow operation increasing this value may make a heavily loaded system slightly more responsive some of the time. However you are more likely to experience performance "glitches" where the database manager has to write a lot of information to disk.
This value is used in conjunction with lazy_threshold.
The database manager will not use any less CPU if you increase this value. The database manager always waits for ever for requests from applications once the cache has been written out.
This option has a slightly different meaning in 4.622. It represents a number of milliseconds to wait for any currently submitted lazy I/O requests to complete before submitting some more. There is probably no benefit in changing this value in 4.622.