I have a OWC 1TB Mercury Accelsior PCIe SSD http://eshop.macsales.com/shop/SSD/PCIe/OWC/Mercury_Accelsior/RAIDand I get 700-800MB/s speeds. There is nothing faster in the market now and it makes the 2010 Mac Pro faster on every level The best $1500 I've ever spent. I am hoping OWC will release updated versions of the Accelsior to add to the new Mac Pro.
OCZ SSD Z-Drive R4 CM84
2000/2000MB/s read/write
faster.