I have the 1640 in an external enclousure with the prolific chip set via
firewire. There is inconsistent amount of time between when i connect
the drive and when it is reconized by windows xp pro fully updated.
Sometimes it is not reconized. Some times i wait 5 mins sometimes 10
mins, never instantly. The usb 2.0 works fine instant reconnition.
After it is reconized everything works fine, can’t burn at 16x, do to
burst rate. How can i fix the firewire issue and be able to burn at
16x. I am using a Sony Vaio 660fs notebook.

try rebooting after you connect also I do not have a link but the 3507 chipset might need a firmware update,you will have to do some searching but the links are in the forum somewhere maybe try external enclosure thread it helped me to update the enclosure firmware

afaik, most external enclosures won’t let burners burn dvd @ 16x even with usb2 & ieee1394a

for recognizing issue, try to find trouble shooting @ sony & check for bios update. as i used few prolific 3507 bridges & i have not had any problems like that so far. also make sure you secure all the cables including ide cable; very common source of all kind of weird problems

you can also try aspi layer driver from adaptec; many said v4.60 is better than 4.7x or you can copy aspi dll to system32 directory; make sure reboot after updating
you can also try 3rd party ieee1394 driver

check this thread

prolific 3507 is (in)famous for many things

try to update firmware as jamescooley1 suggested. you have to connect via usb to update firmware & if you have rev. a chip, you are out of luck

firmware available here

external enclosure thread

since you are using notebook, connecting drive to ide is not impossible but it would be ugly. btw writing dvd @16x isn’t always good as lower speed usually produce better writing quality & would hold you maybe a couple of minutes

good luck