These two devices (external TB RAID vs. internal PCI SSD) operate in somewhat different parts of the (high end) of the bandwidth/capacity plane. Anand (http://

These two devices (external TB RAID vs. internal PCI SSD) operate in somewhat different parts of the (high end) of the bandwidth/capacity plane. Anand (http://www.anandtech.com/show/4489/promise-pegasus-r6-mac-thunderbolt-review/6 http://www.anandtech.com/show/4489/promise-pegasus-r6-mac-th...) found ~700MB/s sequential read/write performance of the TB RAID. He didn't test IOPS directly, although he did put SSDs into the TB RAID and test that (~1000 MB/s). You have to give him credit for that. In short, the sequential performance is pretty close to the real-world sequential performance of the OCZ unit. Which is quite impressive. The Promise RAID-6 I use has 8TB usable (and I got it 2 years ago). The units you mention have just 1TB usable (and no redundancy, which is a problem for big data sets). All this is somewhat academic for my use case, because I dropped my desktop two years ago when TB came out.