In May 2011, SandForce released the first SSD bottlenecked by the SATA III bus. It was just five months after Intel released the P67 Express chipset, Intel's first native SATA III capable release. Until then, PATA and SATA lived long, fulfilling lives, always ahead of the performance curve offered by new data storage products. This fact is just one reason why we call flash-based storage a disruptive technology.
Photo for demonstration purposes only
The standards body, SATA-I/O, quickly jumped into action. The logical choice was to double performance again, going from 6Gbps to 12Gbps. What the group found was that the interface would need signification changes, shielding, and additional development time. This led to additional development time, but in 2013, SATA-I/O published the SATA 3.2 specifications, this time with a viable solution for quick implementation and a way to reduce cost. SATA-I/O went PCI Express.
The move to PCI Express provides an instant performance increase from 6Gbps to 8Gbps via two PCI Express 2.0 lanes. SATA Express standardizes a 2.5" form factor to move the drives away from your motherboard and in the way of multi-GPU configurations.
Moving forward from what we're showing today, SATA Express has several upgrade paths. The first is a shift to PCIE 3.0 where advanced 128b/130b encoding increases efficiency from 80% to 98.5%. Both SATA and PCIe 2.0 use 8b/10b encoding, so 20% of the available bandwidth if used for overhead. PCIe 3.0 reduces the overhead to just 1.5%.
The other option we'll see from controller makers is increasing the number of lanes to the SSD controller, but that won't be possible over SATA Express since it's limited to just two lanes. Over PCIe 2.0 that means 1000 MB/s or 800 MB/s after overhead.
ASUS sent us an early motherboard prototype sample that supports SATA Express. So, let's check it out and see some early performance numbers.