Howdy. Gonna be honest with you...I don't really know much about the HP 630i, but I'm getting to know a bit about the DW1620 (awesome drive, btw). Here's what I found out.
The HP 630i spec page can be found here.
And the BenQ DW1620 spec page can be found here.
Check out these related thread and posts:
[/li]Everything that I find sez...yes. The HP 630i appears to be a rebadged DW1620. I think the confusion seems to be that HP decided to issue their own firmware versions using their own firmware naming scheme.
As many people have done, they've cross flashed to "Bxxx" and it appears to be exactly like an OEM DW1620.
Hope this helps.