Optimize External DVD-R performance?

[Kenshin018]

Hey all,

I'm running a Lite-On DVD-RW SOHW-1673S in an INOI external enclosure (media tank) with an 80gig hard drive inside it as well. It is hooked up to a HP Pavilion zx5000 laptop with 3.4ghz p4 and 1gig of ram. I've tried to burn dvd's a few different ways and I've gotten less than stellar burn times. Ripping the originals onto the computer first, I've tried to burn it from the external hard drive inside the media tank with the burner, which at 16x took 26:35 minutes and from the laptops hard drive, which took 20:22 minutes. This is using Nero 6.0 by the way. Is there anything I can do to get something closer to the actual 16x results or is the best I can expect through this setup and from a USB 2.0?

Thanks in advance for any advice!
Nick