hmm..
i searched the web..
and found out that..
my onboard sound has a SNR of around 107..
but Z5500 has only 93.5....
i think thats the problem..
not with the sound card..
:)
ref - http://www.analog.com/en/prod/0,2877,AD1988B,00.html
http://www.tweaknews.net/reviews/z5500/index2.php