Not yet, that is next on the agenda. 2x HD7970's blocking slots 1-4, controller is in slot 5 at the moment. Full WC so can't really move the GFX cards.

Edit: I know it can do better, I've set up 8x Vertex 3's in a span array on 2x Areca 1880's for a customer a while back, and I got over 3500MB/s sequential in CDM. Just a weird combo of cards and slots, maybe...