SanDisk 240 GB Extreme II SSD Review

SanDisk releases its Extreme II series SSD, which features the Marvell 9187 controller in concert with 19nm eX2 ABL MLC NAND. The competition is heating up as another manufacturer with massive foundry capabilities releases a new SSD. Will the Extreme II "blaze through your day" and "keep you ahead of deadlines?"

SanDisk 240 GB Extreme II SSD Basics

SanDisk's launch of the Extreme II SSD is aimed for the enthusiast crowd with a Marvell 9187 controller and SanDisk's own 19nm eX2 ABL MLC NAND. The Extreme II is the successor to the previous generation SanDisk Extreme we reviewed last year.

The Extreme II features 550/510 MB/s in sequential read/write speed, and 95,000/78,000 random read/write IOPS. Features such as the tiered nCache system improve speed in normal usage patterns and increase the longevity of the SSD.

The original Extreme was a solid performer with an LSI SandForce SF-2281 controller. The low pricing that accompanied the original Extreme made it a great seller, though its performance was typical of other LSI SandForce powered SSDs. LSI SandForce controllers ship with firmware with very few adjustable settings, leading to very little differentiation between the different vendors.

One of the biggest differences between the oringinal Extreme and the new Extreme II is the switch to a Marvell 9187 'Monet' controller. This allows for steady performance even in the face of incompressible data, a significant weakness that LSI SandForce controllers historically do not handle well.

Marvell doesn't provide any firmware for its controllers, leaving that to companies with the resources and talent to develop its own firmware. This byproduct of this firmware customization is high-powered SSDs with unique performance characteristics.

Another key difference is the switch from 24nm Toggle Mode NAND to the new 19nm eX2 ABL MLC Toggle NAND. SanDisk and Toshiba have jointly engineered the new ABL (All Bit Line) architecture for the 19nm NAND. ABL can deliver up to twice the parallelism in comparison to typical HBL (Half Bit Line) NAND. This new technique is designed to deliver enhanced performance and endurance for this new generation of NAND.

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Though the SanDisk Ultra Plus also features this new NAND, the Ultra Plus is designed for low power mobile applications and has lower speed due to its four channel controller. The Ultra Plus also led the way for the new nCache technology developed by SanDisk. This method creates a layer of SLC flash inside each NAND die, creating a fast non-volatile write cache. This enhances speed in bursty random write environments, and enhances the endurance of the underlying MLC NAND.

The Extreme II features 80 TBW (TeraBytes Written) of endurance for all capacity points. This may not sound like a huge amount of write endurance, but this is with pure random write data. In typical use users can expect this number to be two to three times higher with a normal mixture of sequential data. For normal users this amount of endurance will not require any write restrictions, unlike small capacity TLC SSDs.

SanDisk also offers the SanDisk ReadyCache caching solution for a simplistic way to accelerate hard disk drives, rounding out its portfolio.

Being a manufacturer with NAND foundry capability gives SanDisk a big advantage over competitors who do not manufacture NAND. Even among NAND fabricators SanDisk is a big player, its 'Flash Forward' partnership with Toshiba controlled 27.6% of the NAND market in the fourth quarter of 2012.

Taking a look at SanDisk’s operations reveals just how large it is; the Shanghai facility alone delivers over 2 million flash-based products per day. While this mind boggling amount of devices includes USB thumb drives and other small devices, this is still a staggering production capacity. 11 leading PC OEMs utilize SanDisk consumer SSDs, and SanDisk NAND products are also embedded into virtually every leading mobile handset and tablet today. It doesn't matter what form flash takes, SanDisk packages and sells it.

This large presence leaves little doubt that SanDisk will be around to honor the five-year warranty that it includes with the Extreme II SSD. The five-year warranty period is a nice addition. With the shrink down to 1x NAND we are witnessing many manufacturers also shrinking warranties down to 3 years.

Today we will compare the performance of the Extreme II against previous SanDisk SSDs, and the current performance leaders in the SSD market.