G'day Kok-Hong,
I'm just a little confused here, in one paragraph you state:
Quote Originally Posted by kokhong
able to reach between 20%~30% of GbE for iSCSI. That's a more respectable 30Mb/sec for a 2 drive software RAID0.
So the implication is that you are getting 20-30% of 1000 Mbit/s or 200-300Mbit/sec, but the next line you stated 30Mb/s so I assumed you meant 30MB/s(30MBytes or 240Mbits/s), which in my limited experience is pretty good for a 2 Drive Raid 0....

I don't use the 9550, or Onboard Raid for that matter, but I can say that I get around 160-180 Mbit/s Read with an Adaptec 5805 in Raid 5 with 3x Seagate 500GB.

Cheers Ben.