Subject: Storage | June 7, 2018 - 06:08 AM | Allyn Malventano
Tagged: toggle NAND, ssd, PCIe 3.0 x4, ONFI, NVMe, Marvell, controller, 88SS1100, 88SS1084
We've seen faster and faster SSDs over the past decade, and while the current common interface is PCIe 3.0 x4, SSD controllers still have a hard time saturating the available bandwidth. This is due to other factors like power consumption constraints of the M.2 form factor as well as the controllers not being sufficiently optimized to handle IO requests at a consistently low latency. This means there is plenty of room for improvement, and with that, we have two new NVme SSD controllers out of Marvell:
Above is the block diagram for the 88SS1100, an 8-Channel controller that promises higher performance over Marvell's previous parts. There is also a nearly identical 88SS1084, which drops to four physical channels but retains the same eight CE (chip enable) lines, meaning it can still talk to eight separate banks of flash, which should keep performance reasonable despite the halving of the physical channels available. Reducing channels to the flash helps save power and reduces the cost of the controller.
Marvell claims the new controller can reach 3.6GB/s throughput and 700,000 IOPS. Granted it would need to be mated to solid performing flash in order to reach those levels, that shouldn't be an issue as the new controllers increase compatibility with modern flash communication protocols (ONFi 4.0, Toggle 3.0, etc). Marvell's NANDEdge tech (their name for their NAND side interface) enters its fourth generation, promising compatibility with 96-layer and TLC / QLC flash.
Specs for the 8-Channel 88SS1100. 88SS1084 is identical except the BGA package drops in size to 12mm x 13.5mm and only requires 418 balls.
Rounding out the specs are the staples expected in modern SSD controllers, like OTP / Secure Drive / AES hardware crypto support, and NVMe 1.3 compliance for the host end of the interface.
While the two new parts are 'available or purchase now', it will take a few months before we see them appear in purchasable products. We'll be keeping an eye out for appearances in future SSD launches!