Too few Pcie lanes: external raid solution

I'm looking at 3950x as an upgrade to my 5820k.  But dealing with 24 lanes is a bit of a headache.  I've got an old raid 5 setup for my media - an areca 1223-8i that uses Pcie 2.0 x 8. 

I'm toying with the idea of creating an external server and connecting via USB 3.1g2 or 10g ethernet.  Can anyone tell me how much of a performance hit I'd notice (both in terms of latency and sustained data rate) ie would timeline playback be impacted?

I'm assuming I'd set it up as a Linux box, but could I do so and keep my data intact? Does it play nicely with NTFS?. 

Offloading data is not an option at this point. I'd have to dump $1000 on drives.