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Intel Set To Drop NVMe DC P3520 SSD With 20nm 32-layer 3D NAND

By - Source: Tom's IT Pro

Intel's recent 3D Xpoint announcement brought the promise of a revolutionary new non-volatile memory to the forefront, but the deafening roar of publicity over the much-ballyhooed product took the focus off another project that is near and dear to the IMFT (Intel/Micron Flash Technologies) partnership: 3D NAND.

We noticed several new SSDs popping up on the UNH-IOL (University of New Hampshire InterOperability Laboratory) NVMe Integrators List, and a new (and unannounced) Intel SSD was also on the list. After some late-night sleuthing, we turned up an Intel document that details the impending release schedule of two of Intel's newest SSDs, along with a host of information on unreleased Xeon CPUs. We reached out to Intel for confirmation on our findings, but have yet to receive an official response.

We painstakingly researched the information we obtained to ensure that it lines up with other known facts to corroborate our source. One of the unannounced SSDs (DC P3608) is already appearing in several European online retailers -- and the specifications match those in our document. Several other factors, including the close proximity of the 3D NAND timeline to Intel's own stated projections, confirms that our information is probably accurate.

The DC P3608 is interesting, but it isn't nearly as compelling as the DC P3520. Intel's unannounced DC P3520 NVMe SSD comes packing the heretofore-unseen IMFT 3D NAND, which Intel and Micron announced earlier this year. The IMFT 3D NAND packs 32 layers that provide 256 Gb per die for MLC products, and 384 Gb per die for TLC NAND. This equates to a maximum of 512 GB of MLC in a single NAND package, which enables SSDs up to 10 TB within the same slim form factors we use today. IMFT 3D NAND also brings the promise of increased endurance, performance and lower power consumption.

Intel DC P3520
Intel DC P3608
Intel DC P3700
Intel DC P3600
Intel DC P3500
1/1.2/2/3.2 TB
1.6/3.2/4 TB
400/800 GB 1.6/2.0 TB400/800 GB 1.2/1.6/2.0 TB400 GB 1.2/2.0 TB
Random Read IOPS
Random Write IOPS
Sequential Read MB/s
Sequential Write MB/s
Power Operating/Idle12/25 - 4W
25/50 - 8-10 W
25 - 4 W
25 - 4 W
25 - 4 W
Form Factor
AIC & 2.5"AIC Only
AIC & 2.5"AIC & 2.5"AIC & 2.5"
0.35 DWPD
Up To 17 DWPD
0.35 DWPD

According to the document, the DC P3520 Series features large capacity points; even the smallest model packs 1 TB of 3D NAND. There are also 1.2 TB, 2 TB and 3.2 TB DC P3520s on offer. The SSDs will come in both the standard AIC (Add-In Card) form factor and the popular 2.5" format with the U.2 connector is also available. Both models leverage a PCIe 3.0 x4 connection.

The DC P3520 offers up to 450,000 random read IOPS and sustained random write performance of 44,000 IOPS. The random write performance is relatively tame compared to the current-generation DC P3700 series, which has standard 2D NAND and provides up to 175,000 random 4K write IOPS. This is largely due to the read-centric target market for the new DC P3520, which features only 0.35 DWPD (Drive Writes Per Day) of endurance. Even with the relatively light endurance metrics, the SSD still manages to outperform both the mid-endurance DC P3600 and the DC P3500. 

The new SSD falls within the same power envelope as the previous generation DC P3X00 Series SSDs, in spite of the much heftier capacity, due to the low-power characteristics of 3D NAND. The inaugural product features a standard UBER rating of 1 per 10E17 and a 2 million hour MTBF.

Perhaps the most important revelation is that Intel is purportedly utilizing a 20nm lithography for its 3D NAND. Samsung is the only manufacturer shipping 3D NAND products, and it is currently utilizing charge trap flash (CTF) on a 3Xnm node. Other manufacturers have also moved to charge trap and a 3Xnm (or larger) process for their 3D NAND products, but Intel/Micron chose to stay with floating gate.

There are a number of theories as to why Intel chose to stay with floating gate while others have abandoned it, but Intel obviously has the most experience with floating gate technology. Kipp Bedard, Micron's VP of Investor Relations, also weighed in at the recent Jeffries Global TMT conference with the opinion that charge trap approaches suffer from excessive charge leakage, which will reduce the endurance of charge trap products.

Intel and Micron have also been very vocal that they weren't pressured by Samsung's early entrance into the 3D NAND era (nearly three years ago), and that they would produce the NAND when the economics made sense. A much smaller lithography assures the maximum cost efficiency, and 3D NAND can scale either vertically by adding more layers, or IMFT can merely shrink the lithography. Taper width is one of the major challenges associated with vertical NAND scaling, and the 20nm process may exacerbate the issue.

The SSDs will sample in Q4 2015 and will be available for purchase within the same quarter. This schedule lines up nicely with Intel's and Micron's original projections for end-product availability.

Intel is also releasing the DC P3608 in the very near future; as mentioned above, it is already listed at several European retailers. The DC P3608 offers a blistering 5,000 MBps of sequential write speed (easily the fastest on the market) and 2,300 MBps of sequential write speed. Intel also heaps on the performance with 870,000/110,000 random read/write IOPS. The DC P3608 is designed for the mid-endurance segment with a 3 DWPD endurance rating.

DC P3608
1.6 TB
3.2 TB
4.0 TB
Random 4K Read
Random 4K Write
Random 8K Read
Random 8K Write

The DC P3608's impressive performance metrics come courtesy of two controllers and its PCIe 3.0 x8 connection. The x8 connection provides double the bandwidth of the x4 connection utilized with other Intel NVMe SSDs.

The SSD appears as two volumes to the host, and the user can concatenate them into one large volume via the Intel RSTe software. This provides up to 4 TB of capacity and doubles the performance metrics. The DC P3608 leverages standard planar (2D) 20nm HET MLC NAND and features end-to-end data path protection, an UBER rating of 1 sector per 10E17, and a 2 million hour MTBF. The DC P3608 comes only in the AIC form factor, which makes sense because there is no PCIe 3.0 x8 U.2 connector.

We spotted the 4 TB model retailing from $9,081 to $10,624 USD (after conversion), which equates to $2.27 to $2.65 per GB, which is very reasonable in the datacenter segment.

The dual-drive nature of the SSD does present limitations in that RAID 0 isn't exactly known for its reliability. This SSD will require architectures with robust backup and replication protections. Conversely, if both volumes are utilized in a RAID 1 configuration it would provide some level of data protection on a single device. This could help address the risks associated with deploying a single monolithic device, which is one of the key complaints of PCIe SSDs.

The DC P3608 is slated for sampling, and availability, in Q3 2015. I would not be surprised to hear an announcement of this product at next week's Flash Memory Summit, and hopefully more details will emerge at the show on all of the latest topics.

Paul Alcorn is a Contributing Editor for Tom's IT Pro, covering Storage. Follow him on Twitter and Google+.