SanDisk's Ultra Plus SSD is their current mainstream-class SSD. The Ultra Plus is designed to be a low cost, power efficient, lightweight, solid state solution for mainstream consumers. Although the Ultra Plus is designed to be cost effective, SanDisk packed it with the latest technology and superior quality toggle mode MLC NAND.
SanDisk was first to launch a drive equipped with an emulated SLC (Single Level Cell) layer baked into an MLC (Multi Level Cell) NAND flash array. The first SSD to utilize SLC emulation technology is the Ultra Plus. There are currently two other drives on the market that employ SLC emulation technology, SanDisk's Extreme II and Samsung's 840 EVO, both of which are enthusiast-class SSD's.
So, what is SLC emulation and why does it matter? 1 bit per cell NAND (SLC) is the "Good Stuff" because it has vastly superior performance and longevity in comparison to (MLC) 2 bit per cell or (TLC) 3 bit per cell NAND technology. Programming a single bit per cell can be accomplished at a much lower latency than programming multiple bits per cell, and is the reason SLC NAND provides superior performance. SLC NAND is typically rated for 100K P/E (Program/Erase) cycles, whereas MLC/TLC NAND is rated for 0.5K to 5K P/E cycles. The drawback to SLC NAND implementation is cost. SLC NAND is an order of magnitude more expensive to produce than MLC or TLC NAND.
SanDisk came up with a brilliant technology called "nCache". nCache Technology allows a layer of an MLC NAND array to be programmed as single bit per cell. This pseudo SLC layer has lower latency and greater endurance than the rest of the MLC NAND array. nCache Technology is used to accumulate small writes (called segments) at high speed and then flush and consolidate them to the larger MLC section of the NAND Flash memory array there by greatly reducing write amplification. Reducing write amplification is key to an MLC based drives longevity, reliability, and long term performance.
Because SanDisk designed the Ultra Plus for low-cost mainstream user implementation more so than all out performance, SanDisk chose to utilize a low cost, power efficient, high performance Marvell Van Gogh Lite 88SS9175-BJM2 4-channel controller to power the Ultra Plus. SanDisk utilizes their own premium 19nm 400Mb/s interface ABL (All Bit Line) Architecture Toggle Mode 2-bit per cell NAND Flash Memory for the Ultra Plus's NAND array. In essence, the Ultra Plus is an Extreme II with a 4-channel controller and a lower price tag. Having four channels in comparison to eight does reduce all out performance, but surprisingly not by all that much.
Today, we've got a pair of SanDisk Ultra Plus 256GB SSD's in a RAID 0 array. Let's see how SanDisk's current mainstream drives perform in RAID 0 powered by Intel Haswell based SATA ports and Microsoft Windows 8.1.
Specifications, Pricing and Availability
The SanDisk Ultra Plus is available in three capacity sizes - 64GB, 128GB and 256GB. Specifications list the 256GB Ultra Plus SSD as capable of up to 530 MB/s sequential reads and up to 445 MB/s sequential writes. Random read/write speed is listed at up to 82,000/39,000 IOPS at 4K QD32. The Ultra Plus has a 7mm z-height allowing for more compatibility with newer laptops.
SanDisk backs their Ultra Plus series SSD's with an industry standard limited three year warranty. The 256GB SanDisk Ultra Plus is currently available from Amazon for $160 (62.5 cents per GB).
Since this is a RAID article, we are going to focus on performance rather than features. For a more in-depth look at the SanDisk Ultra Plus series feature set, I will refer you to Chris Ramseyer's extensive review of the SanDisk Ultra Plus 256GB SSD.
SanDisk Ultra Plus 256GB SSD
The SanDisk Extreme II comes packaged in a small attractive box that has a picture of the drive on front. The box is grey with red and white lettering. The drives capacity is listed along with a few attributes common to SSD's.
The rear of the box gives us the definition of a gigabyte in ten languages. A yellow logo informs us that the drive is backed by an industry standard three year warranty.
SanDisk includes a stick-on plastic spacer for increasing the drives overall thickness, as well as a printed installation guide.
The top of the enclosure is formed from a single piece of black plastic. Centered on the top face of the drive is a black manufacturer's sticker with red and white lettering.
The bottom and sides of the enclosure are formed from a single piece of stamped aluminum painted black. Centered on the rear face of the enclosure is a manufacturer's sticker that lists the drives part number, serial number, capacity and interface.
Here's what SanDisk's Ultra Plus 256GB SSD looks like completely disassembled. The Ultra Plus has a tiny PCB. The drives controller, DRAM module and two of the drives four NAND chips all make contact with a thermal pad, thereby dissipating heat generated into the aluminum half of the enclosure.
Benchmarks - Test System Setup, Drive Properties & ATTO Baseline Performance
Desktop Test System
The majority of our testing will be done with our test drive/array as our boot volume. Our boot volume is 75% full for all OS Disk "C" drive testing, to mimic a typical consumer OS volume implementation. We're using 64K stripes for all our arrays. Write caching is enabled.
All of our testing includes charting the performance of a single test subject as well as a RAID 0 array of our test subject.
ATTO Baseline Performance
Version and / or Patch Used: 2.47
ATTO is a timeless benchmark used to provide manufactures with data used for marketing storage products.
Slightly erratic performance is seen here in our first test.
We fill our array with random 4K data and run ATTO almost immediately after. This erratic performance tends to smooth out over time after the array has had time to recover from being filled to 75% of its total capacity.
The Ultra Plus array, like most of the arrays on our chart has a temporary performance drop off at 16K transfers. The other arrays on our chart are composed of enthusiast-class and hyper-class SSD's, so it's not surprising to see our Ultra Plus array lag slightly behind in this test.
Benchmarks - Anvil Storage Utilities
Anvil Storage Utilities
Version and / or Patch Used: RC6
So what is Anvil Storage Utilities? First of all, it's a storage benchmark for SSD's and HDD's where you can check and monitor your performance. The Standard Storage Benchmark performs a series of tests, you can run a full test or just the read or the write test or you can run a single test, i.e. 4K QD16.
The software is used several different ways and to show different aspects for each drive. We've chosen to use this software to show the performance of a drive with two different data sets. The first is with compressible data and the second data set is incompressible data. Several users have requested this data in our SSD reviews.
0-Fill Compressible Data
A score of 7800 is what we expect from an array comprised of mainstream SSD's. Read performance/scoring is excellent, approaching hyper-class performance. Write scoring/performance is where the Ultra Plus doesn't perform like our other arrays. As you can see. write performance does not scale as commands stack up. 4K QD1 IOPS are about the same as 4K QD16.
0-Fill Compressible Read IOPS through Queue Depth Scale
This graph clearly shows our Ultra Plus array running with the best of them when reading data.
0-Fill Compressible Write IOPS through Queue Depth Scale
Write caching enables our array to put out nearly three times the performance of a single drive at 4K QD1. The Ultra Plus is equipped with a 4-channel controller and the rest of the arrays on our chart have 8-channel controllers. A 4-channel controller can read as fast as an 8-channel controller, but isn't as fast when writing data.
Compression 100% Incompressible Data
Like the Extreme II, the Ultra Plus is ever so slightly faster when digesting compressible data.
Incompressible Read IOPS through Queue Depth Scale
Reading incompressible data doesn't change the pecking order of the arrays on our chart.
Incompressible Write IOPS through Queue Scale
Writing incompressible data does change the Ultra Plus's performance significantly in comparison to writing compressible data.
The 4-channel controller powering the Ultra Plus can't deliver performance on par with the 8-channel based arrays on our chart, but the performance our array is able to churn out is more than adequate for any mainstream user scenario.
Benchmarks - CrystalDiskMark
Version and / or Patch Used: 3.0 Technical Preview
Developer Homepage: http://crystalmark.info
Product Homepage: http://crystalmark.info/software/CrystalDiskMark/index-e.html
Download here: http://crystaldew.info/category/software/crystaldiskmark
CrystalDiskMark is disk benchmark software that allows us to benchmark 4K and 4K queue depths with accuracy.
Note: Crystal Disk Mark 3.0 Technical Preview was used for these tests since it offers the ability to measure native command queuing at 4 and 32.
Overall we see really nice performance. Write performance does not scale beyond 4K QD1, but 99% of the time, a mainstream user isn't going to exceed 4K QD1 anyway.
Here we see our Ultra Plus array is faster than the Seagate 600 array on our chart. Both arrays utilize essentially the same NAND, but in this scenario, the Ultra Plus array has a slight edge, despite being powered by a controller with half the amount of channels.
The overall write performance of our Ultra Plus array is pretty much on par with the Chronos and Extreme II arrays. Compression is holding back the Chronos arrays performance and the Extreme II arrays performance is being restrained by capacity limitations.
Benchmarks - AS SSD
Version and / or Patch Used: 1.7.4739.38088
Product Homepage: http://alex-is.de/PHP/fusion/news.php
Download here: http://alex-is.de/PHP/fusion/downloads.php
AS SSD determines the performance of Solid State Drives (SSD). The tool contains four synthetic as well as three practice tests. The synthetic tests are to determine the sequential and random read and write performance of the SSD. These tests are carried out without the use of the operating system caches.
Our two-drive Ultra Plus array is able to double the score of a single drive and able to score higher than our enthusiast-class Chronos array.
Benchmarks - PCMark Vantage
PCMark Vantage - Hard Disk Tests
Version and / or Patch Used: 188.8.131.52
Developer Homepage: http://www.futuremark.com
Product Homepage: http://www.futuremark.com/products/pcmarkvantage
PCMark Vantage is the first objective hardware performance benchmark for PCs running 32 and 64 bit versions of Microsoft Windows Vista. PCMark Vantage is perfectly suited for benchmarking any type of Microsoft Windows Vista PC from multimedia home entertainment systems and laptops to dedicated workstations and high-end gaming rigs. Regardless of whether the benchmarker is an artist or an IT Professional, PCMark Vantage shows the user where their system soars or falls flat, and how to get the most performance possible out of their hardware. PCMark Vantage is easy enough for even the most casual enthusiast to use yet supports in-depth, professional industry grade testing.
The reason we like PCMark Vantage is because the recorded traces are played back without system stops. What we see is the raw performance of the drive. This allows us to see a marked difference between scoring that other trace based benchmarks do not exhibit. An example of a marked difference in scoring on the same drive would be empty vs. filled vs. steady state.
We run Vantage 3 ways. The first run is with the OS drive/Array 75% full to simulate a lightly used OS volume filled with data to an amount we feel is common for most users. The second run is with the OS volume written into a "Steady State" utilizing SNIA's guidelines (Rev 1.1). Steady state testing simulates a drive/arrays performance similar to that of a drive/array that has been subjected to consumer workloads for extensive amounts of time. The third run is a Vantage HDD test with the test drive/array attached as an empty lightly used secondary device.
OS Volume 75% full - Lightly Used
OS Volume 75% full - Steady State
Secondary Volume Empty - Lightly Used
As you can see, there's a big difference between an empty drive/array and one that's 75% full/used and one that's in a steady state.
The important scores to pay attention to are "OS Volume Steady State" and, "OS Volume 75% full". These two categories are most important because they are indicative of typical of consumer based user states.
When a drive/array is in a steady state it means garbage collection is running at the same time it's reading/writing. Here we can see the Ultra Plus drives, with half the channels of the other drives on our chart, are incurring a performance penalty is this scenario.
Benchmarks - PCMark 7
PCMark 7 - System Storage
Version and / or Patch Used: 1.4.00
Developer Homepage: http://www.futuremark.com
Product Homepage: http://www.futuremark.com/benchmarks/pcmark7
PCMark 7 includes 7 PC tests for Windows 7 & 8, combining more than 25 individual workloads covering storage, computation, image and video manipulation, web browsing and gaming. Specifically designed to cover the full range of PC hardware from netbooks and tablets to notebooks and desktops, PCMark 7 offers complete PC performance testing for Windows 7 & 8 for home and business use.
We will look to the Raw system storage scoring for RAID 0 evaluations because it's done without system stops and therefore allows us to see significant scoring differences between drives/arrays.
OS Volume 75% full - Lightly Used
PCMark 7 illustrates that write performance isn't as important as read performance overall.
Our Ultra Plus array is able to score nearly as well as the faster arrays on our chart because its read performance is so good.
Benchmarks - PCMark 8
PCMark 8 - Storage Bandwidth
Version and / or Patch Used: 1.2.157
Developer Homepage: http://www.futuremark.com
Product Homepage: http://www.futuremark.com/benchmarks/pcmark8
PCMark 8 FutureMark's latest version of their popular series of PC benchmarking tools. Improving on previous releases, PCMark 8 includes battery life measurement tools and new tests using popular applications from Adobe and Microsoft. Whether you are looking for long battery life, or maximum power, PCMark 8 helps you find the devices that offer the perfect combination of efficiency and performance for your needs.
Use the PCMark 8 Storage benchmark to test the performance of SSDs, HDDs and hybrid drives with traces recorded from Adobe Creative Suite, Microsoft Office and a selection of popular games. You can test the system drive or any other recognized storage device, including local external drives. Unlike synthetic storage tests, the PCMark 8 Storage benchmark highlights real-world performance differences between storage devices.
PCMark 8's Storage Performance Benchmark is an absolute beast of a test. The benchmark beats the hell out of your drive/array for well over an hour resulting in a very thorough evaluation of a drives real-world performance.
OS Volume 75% full - Lightly Used
This testing shows that an Ultra Plus array is capable of outstanding performance that's on par with array's that have 8-channel controllers.
Our SanDisk Ultra Plus array managed to outperform our Seagate 600 array and perform equally to our Mushkin Chronos array.
Secondary Volume Benchmarks - Blackmagicdesign's Disk Speed Test
Disk Speed Test
Version and / or Patch Used: 2.1.1
Product Homepage: http://www.blackmagicdesign.com
Disk Speed Test is an easy to use tool to quickly measure and certify your disk performance for working with high quality video! Simply click the start button and Disk Speed Test will write test your disk using large blocks of data, and then display the result. Disk Speed Test will continue to test writes and reads from your disk so you can evaluate both performance and readability over time.
We rate a drive/arrays video capabilities by the number of different categories that the device is capable of passing. The maximum number of tests that are possible to pass are 45 write tests and 45 read tests. We chart the number of tests a disk/array is capable of passing for a comparison of one drive/array verses another.
It's very hard for a single drive to be completely HD video capable. This is why serious video processing is almost exclusively done utilizing RAID arrays. Sequential incompressible performance is the name of the game when it comes to video processing.
Our Ultra Plus array performs quite well in this scenario and is fully capable of processing high quality video, without causing a data bottleneck.
Secondary Volume Benchmarks - Disk Response Times
Version and / or Patch Used: 1.1.0
Product Homepage: http://www.iometer.org
Download here: http://sourceforge.net/projects/iometer
Iometer is an I/O subsystem measurement and characterization tool for single and clustered systems. It was originally developed by the Intel Corporation and announced at the Intel Developers Forum (IDF) on February 17, 1998 - since then it's become wide spread within the storage industry.
We use Iometer to measure disk response times. Disk response times are measured at an industry accepted standard of 4K QD1 for both write and read. Each test is run twice for 30 seconds consecutively, with a 5 second ramp-up before each test. The drive/array is partitioned and attached as a secondary device for this testing.
Average Disk Response
Write response times benefit most from RAID 0 because of write caching. There is a slight latency increase in read response times for an array vs. a single drive. Our array displays excellent write response and average read response times.
Maximum Disk Response
Maximum disk response times are difficult to nail down because they can vary so much from one run to the next, even when running the same drive.
We chart them anyway, because while they may vary from one run to the next, the chart gives us a pretty good overall picture of what to expect from our particular test subject.
Secondary Volume Benchmarks - DiskBench
DiskBench - Directory Copy
Version and / or Patch Used: 184.108.40.206
Developer Homepage: Nodesoft
Product Homepage: DiskBench
Download here: http://www.nodesoft.com/diskbench/download
We use DiskBench to time a 28.6GB block (9,882 files in 1,247 folders) of mostly incompressible random data as it's transferred from our OS array to our test drive/array. We then read from a 6GB zip file that's part of our 28.6GB data block to determine the test drive/arrays read transfer rate. The system is restarted prior to the read test to clear any cached data, insuring an accurate test result.
Write Transfer Rate
Real-World incompressible write performance is surprisingly very good.
Read Transfer Rate
Wow, look at that read transfer performance!
When writing large chunks of incompressible data, only the Samsung EVO array is able to outperform our Ultra Plus array by the slimmest of margins. This is the first array we've charted running on Windows 8.1, which could have something to do with this outcome. I guess I wasn't expecting to see our Ultra Plus array outperform the Extreme II array, when reading data, but it does.
Even though we're talking about read performance, the reason our Ultra Plus array has faster read transfers than the Extreme II array comes down to capacity. An Extreme II array of the same capacity will have slightly faster read transfers than our Ultra Plus array which you will see in an upcoming report.
Solid state storage is the most important performance component found in a modern system today. Without it, you do not even have a performance system.
SanDisk's Ultra Plus is a great example of a mainstream SSD. It's not the fastest, but it's not intended to be. What the Ultra Plus offers is a low cost solid state storage solution that does not skimp out on performance or quality.
SanDisk chose to outfit the Ultra Plus with their own premium 19nm 400 MB/s interface All Bit Line (ABL) Architecture Toggle Mode 2-bit per cell NAND Flash Memory. In addition, the Ultra Plus is one of only three drives currently available that is equipped with emulated SLC technology.
Looking back at our testing, what stands out to me is how well our Ultra Plus array performed when reading and writing large incompressible data transfers. Even with half the controller channels of the competition, the Ultra Plus held its own, and then some.
SanDisk designed the Ultra Plus with laptops in mind. The Ultra Plus is super lightweight and because of its 4-channel controller design, it is very power efficient. Lightweight, power efficiency and a slim chassis are all attributes that are particularly attractive for laptop implementation. We see the Ultra Plus 256GB SSD a little differently though. We find the Ultra Plus 256GB to be a great path for mainstream consumer RAID 0 implementation. Think about it for a moment; for less than the cost of a typical 500GB SSD, you can get double the performance from a pair of Ultra Plus 256GB drives in RAID 0.
RAIDing two or more drives together provides you with storage that takes performance to the next level and is something I recommend you try. Once you go RAID, there's no going back.