Just ordered the parts for my rig...

[jimx86]

Thank you so much, Jim. That did the trick! Now I can saturate the 1000Mbit/s connection by copying from RAID0 to RAID0.
All copying is done now; the Hack and the Mac Pro are doing their initial TimeMachine backups... This will take a while.

Haha no problem! It's my pleasure! Although all I did was point you in the right direction
Tonymac was the one who provided the actual fix.