Optimize External DVD-R performance?

[EMPiRE]

16x speed burning does not mean that during the whole burning process the burn speed is 16x, it will startout with about 8x speed on the inside and 16x at the outside of the DVD+/-R, so in the end it should be an average of about 10-12x speed

You will never be able to truely burn @ 16x speed as your connected hd's can not burn @ 21MB/s (= 16x speed), so 8x/12x speed is about the max it can do, then it is weird that is can do only 3x (or was this measured at the beginning of the burn?)

But it does not explain the time difference between your 80gig & internal hd as a 7200 rpm disc connected to a usb2.0 port can do about 12-18 MB/s, even a 5400 rpm disc would do fine... so that would be more than enough to not notice any difference...