Marvell introduced its latest line of SATA 6 Gbps controllers, under the 88SE92 Series. The series includes the 2-port 88SE9220, 4-port 88SE9230, and 4-port 88SE9235. All three take advantage of the new PCI-Express 2.0 x2 interface. PCI-Express x2 (2 lanes) has till now only been hypothetically possible, since PCI-SIG has no slot specification for it. With increasing need for system bandwidth while keeping pin-counts and package sizes low by onboard controllers (such as SATA 6 Gb/s and USB 3.0), PCIe 2.0 x2 has emerged as a viable solution based on the proven PCIe 2.0 specification, as PCIe 3.0 is yet to attain maturity in the industry. PCIe 2.0 x2 gives the controller system bandwidth of 1000 MB/s per direction, 2000 MB/s total. This ensures that a connected SATA 6 Gb/s device doesn't face a bottleneck at a given time, something which was impossible on older PCIe 2.0 x1 chips.
This system bandwidth bottleneck alleviation also allowed Marvell to add support for up to 4 SATA 6 Gb/s ports on the 88SE9230 and 88SE9235. All three controllers further support port multipliers. Among the three, the 88SE9230 is the top-of-the-line chip, supporting Marvell RAID software, HyperDuo (Marvell's in-house SSD caching technology), RAID 0, 1, 10 modes, AHCI, and 128/256-bit AES native encryption. The 88SE9235 is a cost-effective variant of the 88SE9230, it lacks RAID, and only features AHCI/IDE modes. It also lacks native encryption. The 88SE9220, the 2-port controller, otherwise supports all the features of the 88SE9230, except of course support for RAID 10 (since it's not possible with just 2 member disks).
More details and a list of the controllers' specifications can be found at TechPowerUp.