External Drive Speed - Thunderbolt vs Firewire 800?

Hi Friends,

I'm looking to upgrade my external firewire 800 enclosure/drives to speed up editing/rendering in FCP 7/X. Currently this is the config I'm using with my MBP:

- Vantech Nexstar dual 3.5" sata external hard drive enclosure ( http://www.vantecusa.com/en/product/view_detail/277 )

- 2 x 1.5TB Seagate Barracudda 3.5" Sata 7200rpm hard drives (http://www.amazon.com/Seagate-Barracuda-7200RPM-Internal-ST31500341AS-Bare/dp/B0 0066IJPQ)

I'm interested in upgrading to an external thunderbolt enclosure like this:

- Pegasus J4 2.5" quad sata3 external thunderbolt hard drive enclosure ( http://www2.promise.com/storage/raid_series.aspx?region=en-global&m=192&rsn1=40& rsn3=62 )

- 4 x Seagate Momentus XT 2.5" sata3 7200rpm hard drives ( http://www.seagate.com/internal-hard-drives/laptop-hard-drives/momentus-laptop/ )

I know I could get better drives, i.e. hybrid hdd/ssd, or just ssd, but that's not in the budget right now.

Can anyone tell me if the thunderbolt enclosure with 4 x 2.5" sata3 drives will read/write much faster than the firewire 800 enclosure with 2 x 3.5" drives?

Thanks in advance !

- Cindy