Is odbc much slower than npgsql?

Hi all,

Recently I found my C/S program becomes slow.  So I analysed the tcp
traffic between my program and the Postgresql database.  I found there
are occasionally tcp re-transmission and that's why my porgram slow
down.

But when I changed to npsql,  the tcp traffic was cut off to only 1/4
and there are much fewer re-transmission.  I am not sure it's the
problem of odbc or it's because that I am using odbc correctly.