I have 2x500GB SATAIII Seagate Baracuda drives in RAID 0 (stripe) on this controller. The read and write speeds are not nearly as expected. I get transfer speeds of approximately 50MB/s and not about 200MB/s as expected. What can I do to improve performance?
Would you please check you are using PCIe Gen2 slot. Would you please try PCIe x16 slot.
Second, you may try another SATA cable.