slow firewire transfer speed in Snow Leopard

Just to let you know that I called the dutch Apple technical support today and that a seconde line support agent opened a case, number 136431075.
I was asked to exexute the Apple capture data software with file system logging on and to provide complete information on my external JMicron chipset Freecom drives (model number and so on) in order to help them reproduce the problem.
Formatting one of my data drives didn't solve the issue, so that I will have to install Leopard in the meanwhile in a dual boot configuration.

Hi again,

Another thread is going on about firewire issues:
http://discussions.apple.com/message.jspa?messageID=10235577#10235577

Amaury

Hello everyone,

I must say that I really tried everything besides the change of kext files. The only way this works for me is to extract with Pacifist the 5 kext files (not the IOfirewireserialbusprotocoltransport.kext alone !) from my Leopard 10.5.6 installation DVD to a random folder (desktop f.e.), without installing them from within Pacifist, and to manually copy the kext files with the Finder to the /System/Library/Extensions folder (be sure to have 5 files dated 10 december 2008), followed by a Disk Utility permissions repair and reboot. I rebooted twice and copied several times up to 10 GB from my Snow Leopard drive to my problematic Freecom firewire drives back and forth and it is really works this time !

Easy way:
1. Please find the 5 Leopard 10.5.6 IOfirewire kext files on my iDisk in a zip file: http://public.me.com/amaurymac
2. Unzip and copy the 5 files to /Systems/Library/Extensions, overwriting the 10.6.1 versions
3. Do a permissions repair with Disk Utility and reboot

Enjoy !

Amaury