apple dvd drive burning too slow

hello there! first post, so forgive any mistake
have a macBook Air with external apple dvd drive (actually the OPTIARC DVD RW AD-5630A) and i'm using with Toast Titanium Pro to burn some DVD's with DivX movie clips.

Problem: it is getting me around 7 / 8 hours to burn a single DVD (no special menus, or whatever...) !!!

Tried several things (disengage PAL encoding for NTSC files; changed for not so best quality, etc...)

any ideas on how to fix this ?

many thanks and keep up the good work!

Well, you are certainly going to be limited by the USB connection, but I would think 7-8 hours is abnormal.

What speed are you recording at? Do you have Toast set at the maximum burn speed? Is the entire time the actual burning process, or is it encoding during the majority of that time?

Does it say Encoding for a long time before the burn starts? The burn itself should not take very long, but it's converting the movie to the DVD format that takes some time.