Micron RealSSD P320h PCI Express SSD Review

Introduction and Specifications

We've often spoken about the future of SSD technology eventually evolving away from "bridged" interfaces like SATA and SAS, to direct-attached, native interfaces like PCI Express.  It just makes sense.  With the ultra-fast random access times and high IO bandwidth of solid state storage, it's not the storage media itself that's the limiting factor, rather, non-native interfaces get in the way and become the bottleneck. A SAS or SATA controller still has to have its protocol translated over to PCIe so the host can talk to it, which wastes precious bandwidth and adds latency.

Most of the PCIe SSD cards on the market today, with the exception of products from Fusion-io, still rely on SATA or SAS-based NAND controllers to interface on the backend of the device to the NAND array. PCIe cards from OCZ, Intel, LSI and others use controllers from LSI SandForce or the like.  Fusion-io was the first company to introduce a true native PCI Express to NAND Flash controller-processor employed in their products, though Micron has also been cooking up their own native PCIe SSD technology for some time now.

Today we're looking at the Micron P320h, a PCI Express SSD that was introduced to the market well over a year ago and has actually been shipping to OEM customers for some time, but is just now hitting the market for general availability.  Micron partnered with IDT, a veteran semiconductor manufacturer out of San Jose that specializes in high speed serial switching and memory interface technology, for co-development of the product.  A match made in high bandwidth heaven, between a bellwether memory giant and a cutting-edge high speed logic manufacturer?  Perhaps.  Read on as we find out.

Micron RealSSD P320h HHHL PCI Express SSD
Specifications & Features
  • Capacities:  350GB, 700GB
  • NAND Type:  SLC (Single Level Cell)
  • Interface:  PCIe (Gen2-compliant) x8
  • Sequential Read Bandwidth:  Up to 3.2 GB/s
  • Sequential Writer Bandwidth: Up to 1.9 GB/s
  • Random Read Throughput:  Up to 785,000 IOPs
  • Random Write Throughput:  Up to 205,000 IOPs
  • Read Latency:  <42μs (512 bytes) posted
  • Write Latency:  <9μs posted
  • Lifetime Endurance:  (Total bytes written) 350GB SSD = 25PB; 700GB SSD = 50PB (Petabytes)
  • Error Correction or ECC
  • Hardware-based NAND translation
  • Hardware-based Wear Leveling
  • Hardware-based Reclaim or Garbage Collection
  • RAIN/RAID Management (Required over-and-above ECC in any NAND array for enterprise level data integrity)
  • Active Power Consumption:  25W max
  • Form Factor:  Half Height Half Length
  • Operating Temp:  (0°C to +50°C)
  • Dimensions:  68.90mm x 167.65mm x 18.71mm
  • One unit quantity price: $6,995

The primary difference in what Micron and IDT have partnered together to build, versus what Fusion-io has developed, is that the co-developed Micron-IDT solution is a ground-up custom ASIC design, whereas Fusion-io relies on FPGAs (Field Programmable Gate Arrays) to implement their technology.  At least in theory, there is a high degree of hand tuning involved in custom ASIC (Application Specific Integrated Circuit) design implementations, versus programmable logic (FPGA) chips.  The latter of which, from a volume production standpoint, is also generally more costly as well. (Full disclosure:  I used to work for IDT as a Field Sales Engineer.)

The IDT ASIC follows the emerging NVMe standard of optimized PCI Express SSD Interfaces.  IDT purpose-built this ASIC with Micron for their application but also has a number of similar devices available now on the open market.  The 89HF3208 is a 32 channel NAND controller with a X8 PCI Express interface that is both Gen 2 and Gen 3 compatible, though Micron's P320h card is currently only validated for Gen 2 operation.  The IDT 89HF3208 is a rather large 1517 pin FCBGA (Flip Chip Ball Grid Array) packaged device, which is understandable with a 32 channel NAND memory controller on board.

Regardless, the net result of what Micron and IDT have pulled together here is a X8 PCI Express SSD that claims monster performance numbers of up to 785K IOPs for reads and 205K IOPs for writes, along with over 3GB/s and 1.9GB/s read/write bandwidth, respectively.

The Micron P320h isn't cheap though.  At a one piece price of $6995, this is an SLC (Single Level Cell) NAND solution that is squarely targeted at high availability, high throughput data center and enterprise applications.  Let's take a closer look at what makes the Micron P320h tick.

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