Speeds of Bad Firewire Cards

I thought the difference in speed between an iffy PCI FW card on an emailer's G5 and the built-in FW800 using the same hard drives and same cables was intersting. It's the difference between a 3+hour copy and a 22min one. I'm not sure what the cause is as they're still trying to troubleshoot it.

Good Speed:


Bad Speed: