USB3 vs TB2...When does TB make a difference?

[arbitrage]

I'm looking at DAS solution which will likely be a 4 disk RAID 5 array. Probably going to buy from OWC as I also have to order memory from them for new iMac and another USB stick. I would also like to have another backup cloned drive of the data stored on the RAID 5 system.

Will I benefit from having the TB2 DAS solution or would I gain nothing without using SSD drives (which I don't plan on doing)? I would be using standard 3.5" drives (not sure which ones yet 5400 vs 7200 and brand).

This will mainly be for storage of RAW files for photography and a backup of movies and iTunes etc...

OWC has there ThunderBay 4 RAID with TB2 or they have their Mercury Elite Pro QX2 which has USB3, FW800 and eSATA. Both are 4 bay systems but just with different connections. Obviously the USB3 system is a bit cheaper and I think comes with 7200 drives where I'm not even sure what drives come in the ThunderBay one. I could also buy my own drives.

I guess the other issue is TB2 would allow me to daisy chain another backup clone drive onto the RAID system without using another port on my iMac.

Any and all advice is very welcomed. Thanks.

 

[One Cool Cat]

As far as I remember one of the benefits of Thunderbolt is the sustained R/W speed compared to USB3. While USB3 is rated at 640 MB/s, for large files the speed will taper off to a speed lower than what Thunderbolt would deliver on a consistent basis. Photo RAWs would not benefit much from sustained speeds due to their relatively small sizes, but movies and large files would. But even then, the duration would be a difference of a few minutes and I don't believe that would be worth the extra money.

But then again, if you're using regular platter hard drives then I doubt the speed benefits will be worth the markup. If it were an array of SSDs then I would argue for going with thunderbolt.

 

[ColdCase]

TB is much more OS friendly for storage or video applications, virtually no quirks (like waking from sleep, mounting speed, or SMART status). TB is a well controlled interface, USB3 is the wild west with numerous interpretations of specs leading to some interesting compatibility issues. TB performance makes a difference more in RAID and SSD type environments, especially software RAID solutions and when there are several disks hanging off the bus. I dunno why you are going RAID 5, but if thats an enclosure hardware function you may not observe much performance difference.

I am a much happier camper now that I'm using TB for my office storage and USB only for portable storage, phones, cameras... You could get lucky, however.