I bought a couple of very fast 16X combo burners (Pioneer, I think.. don't have them handy here at the moment to check, though). Speed sucked under MS-Win, until I did some kind of reinstall of some widget or something. Now burns at very fast speed.

Verbatim DVD-DL media burns at 8X, and regular SL media averages around 12X over the burn interval, peaking at 16X as expected.

Cheers