Fireware 800 is TERRIBLE, the connections get loose and you have digitizing problems.
I have Media 100i xr boards with the latest software, in an G4 at 1.42Ghz.
I bought from FirmTek the “Big Boy Bundle”: One External 4-Bay eSATA Enclosue with Card
see: https://store.yahoo.com/firmtek/sata2even4.html
That provides over 300 MB/sec transfer rate to the drives and MORE than enough for uncompressed video with the xr option. And the drives are removable!
The engineers I spoke said to only buy thye Hitachi SATA-II dives, either the 250Gb drive or the 500Gb drive. The Hitachi SATA-II 250Gb drive costs only $109.
This is very inexpensive and BLOWS away Firewire 800 which is worthless!