With the release of the SSD DC P3700, Intel has delivered on the most anticipated piece of storage technology in recent memory. This release is all about NVMe. We have been hearing about NVMe for years, but an end product always seemed just out of reach. We also expected the first devices to be exorbitantly priced enterprise SSDs. While not the first to market, the Intel solution will be available to the masses and it will be priced to move. This is not something you can always count on for an enterprise product.
So, what makes NVMe special? NVMe is a host interface controller specification that is a complete replacement for AHCI. For those keeping track at home, AHCI is currently in its second decade of release and is in dire need of replacement. AHCI was released at a time when storage meant rotating drives and AHCI was designed around that fact. If you wasted a few extra clock cycles with AHCI, the latency in the physical media was more than enough to mask those inefficiencies. Today, NAND and the physical interfaces are at a point where microseconds of delay can affect performance.
Looking at a simplified graph, NVMe brings the storage closer to the CPU. While NAND latency stays the same, you are reducing/removing a large portion of the software and controller latency. This shifts the burden back to NAND manufacturers for improvements going forward. It also reduces the number of clock cycles required per IO. This should allow for high IOPS environments to have reduced CPU loads.
We have to be honest, even we were excited when we received this product in the mail.
Unlike SATA drives in the past, Intel didn’t just announce a single SSD, they announced 3 different products, all with different capacities and performance. The names should look familiar as they closely match their SATA line. Intel breaks the products up based on write endurance (or NAND quality). All of the options are available as PCIe add-in-cards or SFF-8639 2.5″ drives and all use a PCIe Gen3 x4 interface. Performance ramps up to an astounding 460K read IOPS and 180K write IOPS.
What probably catches most peoples eye is the price. With the P3500 coming in at $1.50/GB, it is priced well below the competition. In fact, it is a range that many people might think to use it in a hobbyist system.
Our review unit is the PCIe 800GB P3700. The exterior looks fantastic and has a great weight to it; it feels like a premium device. Now, most of that will be lost once it goes into a server, but the looks are also functional. The single PCB is covered on one side by a large heatsink that helps dissipate the 25W that the card can consume.
Our sample was outfitted with 36 NAND packages. Each package contains Intel 20nm HET-MLC. This high endurance NAND is what allows the P3700 to hit 10 drive writes per day of endurance. Intel let us know that the P3700 has ~25% spare area, while the P3600 has ~12% and the P3500 has 7%. This amount of spare area is typical for these types of drives.
Out review unit is a x4 Gen3 PCIe add-in-card, but the product line also comes in a 2.5″, 15mm form-factor. While this size might look familiar to enterprise customers, the connector probably does not. That is because Intel chose what will soon be the most common connector for enterprise products, SFF-8639. This connector specification is the Swiss Army Knife of storage connectors.
As you can see, every single current and future interface is supported on the same connector. What is beautiful is that it is backwards compatible with SATA and SAS. If you don’t believe us, go ahead and pick up any SATA or SAS device and look at all the extra room on the opposite side of the connector. SFF-8639 takes that space and uses it for the x4 PCIe lanes, SMBUS lines and PCIe clock and reset. With this setup, an enterprise system could be configured in a way that any current and future drive could be supported in a single slot.