If you thought PCIe SSDs have killed performance SATA products, you are wrong. While PCIe is the next great frontier, the transition will take time. Current consumer PCIe based SSDs still use the AHCI command set, the same as SATA, so the latency is nearly the same. It doesn't matter if your shiny new PCIe SSD talks directly to the host CPU or routes through the PCH; AHCI is the limiting factor for latency. That will eventually chance once NVMe goes mainstream, but that day is not today.
SanDisk has already built a PCIe device but never brought it to the channel. We tested the A110, and although it was damn fast at the time we tested it, the Extreme II delivered better all-around performance while only trailing the A110 PCIe SSD in sequential performance.
The SanDisk Extreme II was the fastest consumer SSD to hit the market. Even though limited by the SATA III interface, the Extreme II delivered on what I call the third plane: dirty state performance. We often talk about SSDs in two dimensions: random and sequential performance. Both are advertised specifications but easy to understand. The third dimension is what we first looked for in our Data on Disk (Fill Testing) back in 2011. That eventually led to a meeting with Futuremark in 2012 and finally to PCMark 8's Advanced Storage testing that we use today.
Over the last year, this extra level of measureable performance has come in many forms. 4k write consistency, first on the pages of TweakTown, works well for enterprise testing but is useless for client products since none of us will ever write 4k random data to the drive for hours at a time. The best test we've found to date is the PCMark 8 Advanced Storage test because it shows performance through the different stages of use, just like we find in the real-world.
That brings us to the real-world, where SanDisk tuned the Extreme PRO. We read and write data at the same time, not the one or the other environment that we've tested SSDs in for many years. Tuning a SSD for real-world workloads has a down side, and the marketing numbers are lower since the product isn't tuned for one-at-a-time read or write tests. When looking over the Extreme PRO specifications, keep that in mind.
Specifications, Pricing and Availability
SanDisk went with three capacity sizes for the Extreme PRO: 240GB, 480GB, and 960GB. These are overprovisioned capacity numbers. Each drive has flash area reserved for background activity like garbage collection and other flash management tasks. The sequential read performance for all three capacity sizes is the same at 550 MB/s. The sequential write performance is a bit higher on the 240GB model, coming in at 520 MB/s, while the 480GB and 960GB models provide 515 MB/s. SanDisk is very conservative with their published performance numbers.
Performance measurements come from a system with C-states enabled, with a stock processor speed, and in Crystal Disk Mark. This ensures everyone, including reviewers, is able to achieve the published specifications. It also means a mildly tuned system will allow the Extreme PRO to perform much better than the claimed performance numbers.
Random reads and writes come in at 100k IOPS read and 90k IOPS write. Over the past several months, several products tested performed significantly slower in smaller capacity sizes. SanDisk didn't follow suit with the shift to 128Gbit die that robs lower capacity products of performance. The entire Extreme PRO series uses premium 1Ynm (A19, 19mm x 19.5mm) ABL MLC Toggle flash in 64Gbit capacity. While more expensive than using 128Gbit die, 64Gbit allows for higher interleaving and thus higher performance. The Extreme PRO is a performance product despite the mild specifications. We'll talk about that extensively in our conclusion.
To coincide with the release of 1Y 19nm flash, SanDisk has also updated nCache. nCache debuted on the Ultra Plus SSD quite a while ago and went unchanged on the Extreme II SSD a few months later. The technology of using a small amount of MLC flash in SLC mode has gone bi-directional in the latest revision, and it is now optimized for mixed workloads. SanDisk calls the latest revision nCache Pro.
Until you see the actual performance data, the biggest news surrounding the Extreme PRO series has to be the new 10-year warranty. To put 10 years into perspective, I tested the fastest consumer hard drive on the market 10 years ago, a Western Digital Raptor with 74GB of capacity. For some of you, that was enough, but to really drive the point home, ten years ago Cameron was at Quakecon in Texas and a majority of PC gamers still used bulky CRT monitors. SanDisk's commitment to Extreme PRO users isn't just a nice marketing pitch either. As one of only six NAND flash manufacturers, the company will be around ten years from now to support the products.
Another new feature with the Extreme PRO actually works with SanDisk's entire consumer SSDs. SSD Dashboard is free for all SanDisk SSD owners and works to keep system performance high and give users additional value added features such as drive cloning. At the time of writing, not all of the features were working. In the coming weeks, we'll have an SSD Software Face-off and compare each company's software. You can download the Dashboard software for your SSD here.
At the time of writing, SanDisk already sold every Extreme PRO SSD allocated to Amazon. Newegg also sold out of the 960GB capacity size. The current prices are $269.99 (240GB), $399.95 (480GB) and $599.99 (960GB) at Newegg, but the 240GB and 480GB are over SanDisk's MSRP. You should expect to pay just $189.99 for the 240GB model and $369.99 for the 480GB model once the warehouse has adequate stock. Inside the package, SanDisk includes a 7mm to 9.5mm adapter, but that is the extent of the accessory package.
PRICING: You can find the SanDisk Extreme PRO (960GB) for sale below. The prices listed are valid at the time of writing but can change at any time. Click the link to see the very latest pricing for the best deal.
United States: The SanDisk Extreme PRO (960GB) retails for $699.99 at Amazon.
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