Marvell 88SS9174-BLD2 SSD Processor

For those who can still remember the occasion, back on February 2010 Micron Technology introduced the Crucial RealSSD C300 solid state drive. This was the first consumer-level SSD to support the cutting-edge SATA 6Gb/s interface, known by some as SATA-III. Back then, Crucial's RealSSD C300 was able to reach 383/227 MBps read/write speeds on a Marvell controller in our lab tests. Just over one year later, they've returned to deliver its sequel rated for speeds up to 415 MB/s: the Crucial m4 Solid State Drive. The Crucial RealSSD-C300 was the industry's first SATA 6Gb/s consumer solid state drive, and also the first SSD to use ONFI 2.1 synchronous NAND flash. But with a 355/215 MB/s read and write speed rating from its Marvell 88SS9174-BJP2 SSD processor, the C300 was ready to be replaced.

Micron equips the RealSSD C400 with the revised Marvell 88SS9174-BLD2 SSD processor. Marvell's 88SS9174 (aka "9174") controller is used in the following solid state drives: Micron RealSSD C400/Crucial m4, Strontium SSD Matrix, Intel SSD 510 (BKK2 revision), Corsair Performance 3 (BKK2 revision), and many more. This controller is based on the same processor that powered the C300, but its been tweaked to output 90,000 combined IOPS based on Micron's own Iometer tests. In this article, we examine just how much has changed 'under the hood' with the new Crucial m4/Micron RealSSD C400 series.

Marvell's BLD2 revision of their popular 88SS9174 controller offers a few primary differences from the older BJP2 varient, and a few good reasons to consider their storage product over the competition. The 88SS9174-BLD2 offers faster transfer speeds, improved write IOPS, and support for Micron 25nm MLC NAND flash modules. The Marvell SSD printed circuit board (PCB) follows the same general design as several past products, with a familiar component layout complete with NAND flash modules, DRAM buffer, and Marvell 88SS9174 controller.

Marvell's solid state drive processor is joined by up to sixteen 25nm flash NAND flash memory arranged in an 8-channel design, and a single DRAM chip for buffered transactions. The Marvell 88SS9174 supports Native Command Queuing (NCQ) with 32 command slots. Similar to other modern SSD controllers, the Marvell 88SS9174-BLD2 processor was built to support native TRIM and Secure Erase commands. Additionally, the Self-Monitoring, Analysis, and Reporting Technology (SMART) command set is also supported. Bandwidth estimates for the Marvell 88SS9174-BLD2 SSD controller claim speeds up to 415 MB/s read-from and 260 MB/s write-to, however these are dependant on the flash-NAND and DRAM buffer used.

Our Marvell test sample was pulled from a Crucial m4/Micron RealSSD C400 SSD. Since Crucial is a Micron brand, it's not surprising to see Micron NAND used in their solid state drive. The flash NAND used on the 256GB CT256M4SSD2/MTFDDAC256MAM-1K1 model are built with 25-nanometer technology and utilizes Micron's high-speed ONFI 2.1 NAND interface for 166 MT/s with 512-byte industry standard sector size. Each 32GB Micron 29F128G08CFAAB MLC NAND module requires 3.3V, and yields a total NTFS formatted capacity of 223 GB in Windows 7.

In addition to Marvell 88SS9174-BKK2/BLD2 SSDs, this same 25nm Micron MLC NAND flash component is used on SandForce SF-2200 series SSDs such as the OCZ Vertex 3.

The ONFI 2.1 specification pushes NAND performance levels into a new performance range: 166 MB/s to 200 MB/s. This new specification is the first NAND specification to specifically address the performance needs of solid-state drives to offer faster data transfer rates in combination with other technologies such as SATA 6Gb/s, USB 3.0 and PCI Express Gen2.

After the SSD processor and NAND flash, all that remains is the DRAM buffer. While other 256GB Marvell-based storage devices such as the Intel SSD 510 and Corsair Performance 3 receive only a 128MB cache transaction buffer, the Crucial m4/Micron RealSSD C400 and Strontium SSD Matrix each get the benefit of a 256MB DRAM module. Micron's 256MB DDR DRAM module (ICD22-D9LGQ) offers decent cache performance for fast transaction buffering, which will become more important as SATA 6Gb/s transfers are observed.

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