I'm referring to HBAs, never got or seen someone get more than about 3000MB/s with a x8 PCIe 2.0 HBA and 6000MB/s with a PCIe x8 3.0 HBA, won't say it's not possible, just not typical, and we are talking about a HBA here. AFAIK it's not part of the SAS3 spec, LSI has Databold, PMC mentions "SAS and SATA edge-buffering preserves customers' investment by improving performance with existing 3G and 6G drives", but in any case the wide link is never 12G native, so some performance degradation would be normal, I expect that if I used SAS3 devices with the 9300-8i and the expander I would get closer to the 6400MB/s typical speed announced.