RAID Firewire 800 vs RAID USB 3.0 (5400RPM)

I have 2 external HDDs, same model. They have USB 3.0 and 2x Firewire 800 ports for daisy chain. The drives are 5400RPM

I want to RAID 1 them so they appear as a single volume on the Finder. Should I use USB3.0 or should I daisy chain them in order to make this RAID?

I am asking cause I heard USB 3.0 consumes too much CPU and bandwitch in the background and Im not sure if the drives are fast enough to saturate the Firewire 800 connection. I really welcome an expert advice

Well, replying myself, in case anyone is interested:

I made tests with both the USB and the Firewire drive and my 2 internals SSDs. I moved around a 1GB file across the drives.

I tested both USB 3.0 and USB 2.0 speeds on the exact same external HDD, a WD My Passport 3.0. I made the 3.0 test on a MacMini with USB 3.0 and Firewire 800 ports and then the 2.0 test on a white macbook with USB 2.0 ports. The macbook also has a SSD inside, same model as the MacMini's SSDs. Here are the results:

SSD1 to SSD2: 5s
SSD2 to SSD1: 5s

SSD1 to USB2: 24s
SSD1 to USB3: 24s
SSD1 to FW800: 25s

USB2 to SSD1: 36s
USB3 to SSD1: 40s (what the?)
FW 800 to SSD1: 23s

Apparently there is no diference what so ever for 5400RPM USB 3.0 HDDs or 5400RPM USB 2.0 HDDs or 5400RPM Firewire 800 HDDs

All connections have showned a maximum ability to read/write a 1GB file in aprox 24 seconds due to Hard Disk limitations. For some reasoe, the USB technoly has some trouble reading making the task even slower.

BONUS TEST: SSD1 to a Firewire drive daisy chained, target being the drive on the far side of the chain

SSD1 to FW800: 25s
FW 800 to SSD1: 33s

For some reason, when the drive is daisy-chained, Firewire technology also has trouble reading the file, but is still faster then USB 2.0 and USB 3.0

Firewire is a light winner according to the tests.

chambord said:

I found FW800 to be infinitely faster than USB2, which doesn't quite match your numbers.

Can anyone explain these findings?

Click to expand...

Perhaps the hard disk on the USB drive is slower then the hard disk on the fire wire. These things things are very "each situation is unique"

Im believe a 7200RPM USB 3.0 drive will be faster then a 5400RPM Firewire drive. Im sure a SSD USB 3.0 drive will be faster then a 5400RPM drive

But as 99% of external HDDs are 5400RPM, I would say Firewire is the best techonlogy to use this drives, specially cause you can daisy-chain them using only 1 port.

I believe USB 3.0 and Thunderbolt to be the future, but the drives need to be SSD.