I did use the 2 clean tools from Nero.
I think I narrowed down the problem:
I have my 80 pin IDE cable, the furthest end is my 1620, the nearest to the actual physical ide controller is my 1650.
I put my 1620 as "slave" using the jumper, and 1650 as "master"
Furthermore, I let WindowsXP SP2 rename my 1620 drive to "G" and 1650 as "H"
After I removed my 1650 from the ide cable, and put my 1620 to "master", Nero was once again burn at 8x.
I guess either Nero either didnt like the cabling, or didnt like my changing the drive letters around in Windows.