Sunday, November 14, 2010

Roundup: The Best SSDs For Enthusiasts

The SSD market continues evolving. We got our hands on six drives we hadn't yet tested, including Samsung’s 470-series, and ran them through our benchmark suite. All told, this roundup includes a total of 24 SSDs to compare. Which drive is right for you?
The solid state drive (SSD) market now spans from $80 all the way up to roughly $700. Within this range, you’ll get capacities between 30 GB and 256 GB. All modern SSDs are fast enough to outperform conventional hard drives, and all will improve system responsiveness and performance by a noticeable margin if used as a system boot volume. At the same time, SSDs consume less power than hard drives and are far more rugged. This article looks at seven SSD products and compares a total of 24 drives in the benchmark section. Welcome A-Data’s Nobility N002, the Corsair Force F160, Kingston’s SSDNow V and SSDNow V+, the Patriot Inferno, and the brand new Samsung 470-series.

SSD Market Overview
SSD vendors often base their designs on one of a few popular controllers and architectures. Alternatively, some vendors simple purchase and re-label entire drives. The number of SSD vendors continues to grow as companies anticipate a burgeoning market and attractive profits.
Most of the silicon architecture is available from Indilinx, Intel, JMicron, Marvel, Samsung, SandForce, and Toshiba. Seagate and Western Digital have solutions, but they’re not yet very relevant in the SSD world. There are several NAND flash memory manufacturers too, including Hynix, Intel, Micron, Samsung, and Toshiba, but only two SSD makers actually control their entire manufacturing process from controller design to NAND flash production to final assembly. The focus here should be on the fact that these manufacturers can; it doesn’t mean that they always do.
Controllers Matter
SSD vendors have some room for optimization, such as in the firmware and how they configure flash memory channels. Therefore, it’s only possible to generalize about how an SSD with one controller type or another should perform. Only an in-depth product review will provide the full picture.
This is the PCB of Corsair’s F160 SSD, based on SandForce’s SF-1200 controller and Intel NAND flash memory.This is the PCB of Corsair’s F160 SSD, based on SandForce’s SF-1200 controller and Intel NAND flash memory.
It’s important to put controllers in the spotlight, because most SSD innovation happens on this front. All SSD vendors utilize similar flash memory types. Clock speeds have been increasing a bit, but all production MLC NAND flash memory still stores two bits per cell. In reality, it’s the controllers that are responsible for most performance tweaking and faster interface bandwidth.
Fortunately, future products will be able to store more than two bits per cell, yielding increased storage density and capacities. Today, the biggest news going is Samsung’s toggle mode DDR NAND flash memory, which applies double data rate technology to NAND flash memory. This could double theoretical throughput and is now available on the new 470-series, included in this article.

Benchmarking Issues
We had a phone conference with Samsung engineers after finalizing our first benchmark runs on the 470-series. Performance numbers were encouraging, if not mind-blowing. We had a healthy discussion about benchmarking tools, as Samsung pointed out a possibly-critical limitation with c’t magazine’s h2benchw 3.6 tool. This is by far one of the best apps for accurately testing throughput across the full storage area of any drive, regardless of partitions. It returns a CSV file that allows users to draw data transfer diagrams. These show the average and minimum transfer rate results imperative in identifying throughput-oriented spikes and drops. Many SSDs are impressively fast, but we believe it’s almost as impressive to look at how slow they could be in a worst-case scenario.

h2benchw can cause issues because it doesn’t generate random data for writing. Instead, it writes only zeroes. This has not been an issue with hard drives nor with most SSDs, which treat all writes equally. However, SandForce’s “DuraClass” architecture works without a dedicated cache memory and utilizes some of the main flash memory for caching, load balancing, and countering write amplification. Since the algorithms are potentially smart enough to turn cache data into user data or to take advantage of data compression, this may represent a benefit for SandForce-powered SSDs.
For this reason, we followed Samsung’s recommendation and ran most of the SSDs on CrystalDiskMark 3.0, as well. It isn’t comprehensive enough to look at a drive’s overall throughput performance, but it’s very handy for assessing the performance potential of SSD products.
PCIe SSDs Coming Up
Finally, the issue of bandwidth limitations might come to an end in the foreseeable future. The SSD Form Factor Working Group was recently founded by Dell, EMC, Fujitsu, IBM, and Intel in an effort to simplify SSD installation and maintenance. Other companies such as Amphenol, Emulex, Fusion-io, IDT, Marcel, Micron, Molex, PLX, STEC, SandForce, and Smart Modular Technology are Contributor Members. Collectivley, the group will primarily be working on interfaces and form factors. One predictable result will be a connector and interface specification that will support storage over PCI Express 3.0 and include better interoperability with SAS/SATA 3.0. Improved hot plugging is another priority.
Future SSDs will most likely be limited to a 6.35 mm z-height. A slimmer design will enable significantly higher storage and I/O densities in high-performance environments. Today’s SSDs are typically housed in 7 mm or 9.5 mm housings on the 2.5” form factor.

Did Corsair name the Force series because it’s based on SandForce controllers? Is it a play on Air Force? Either way, the drive is jet fighter-fast on 4 KB random write operations I/O performance, even if it lags a bit on throughput. We’d also love to see better throughput in the CrystalDiskMark 3.0, as well as better minimum transfer rates in our h2benchw 3.6 benchmark.
The reason for this throughput performance behavior can probably be found in Corsair’s memory installation. The architecture is laid out for a maximum capacity of 320 GB. A maximum of 16 flash memory ICs can be accomodated on the PCB. The 160 GB model uses 12 Intel 128 Gb MLC NAND NAND chips soldered onto the board, bringing the drive to a gross capacity of 192 GB. Keep in mind that the SandForce controller utilizes part of the flash memory for caching, leaving about 180 GB. We don’t exactly know how the controller drives its memory, but somewhere there has to be an explanation for minimum transfer rates dropping to 180 MB/s while peak throughput stays competitive.
The Force F160 reaches one of the higher positions in our PCMark Vantage testing. This one includes several real-life load scenarios and conveys how the drive performs under these conditions.
We can’t complain about the drive’s power consumption, which is slightly lower than other SandForce-powered SSDs. Although the Force F160 can’t dip to power levels seen on SSDs with fewer ICs or newer products, such as Samsung’s 470-series, it delivers great overall performance at relatively low power, a three-year warranty, and a set of 2.5” to 3.5” mounting brackets for desktop users.

The SSDNow V (which implies value) is an affordable option for users who are looking to make the switch from HDD to SSD, but without high-end performance requirements. Kingston offers 30 GB, 64 GB, and 128 GB capacities. The 128 GB model we tested sells for roughly $230. This is a decent deal, given that performance SSDs easily reach the $300 line. Enthusiasts will want the SSDNow V+, but mainstream consumers might prefer this more affordable model.

The SSDNow V doesn’t perform well on 4 KB random writes, and we found that write throughput can drop quite a bit, as well. The minimum write throughput measured with h2benchw was only 15 MB/s. However, this still wouldn’t hurt productivity or multimedia users much, since the throughput average of 138 MB/s is sufficient and read performance stays consistently above 200 MB/s. CrystalDiskMark 3.0 also proves that the drive can compete with similar products on throughput.
Application performance using PCMark Vantage is below average, and we also found that idle power is significantly higher than expected: 1.36 W, which is several times more than competing drives. This is obviously more important for runtime-hungry laptops than desktops. The same applies to power at high I/O activity or maximum throughoput.
In the end, the SSDNow V provides fast throughput numbers, but quickly falls behind other drives once high I/O activity or high application performance is required. Enthusiasts should look elsewhere because the overall performance lags behind the competition. For all other users, the low price should beckon.
Update: Just prior to this story going live, Kingston announced the V-series' successor called the V100. It employs the same JMicron-based controller, but employs Toshiba's 32 nm NAND flash, requiring a firmware update. We'll be including that drive in an upcoming comparison.

Our second Kingston SSD product is the SSDNow V+, which rests a notch above the “value” group, while still not climbing to enthusiast levels. It isn’t based on the regular V model’s Toshiba controller. Instead, Kingston utilizes Toshiba’s Daikoku 2 T6UG1 controller, which isn’t as strong on 512 KB random writes, but is fast at most other types of sequential reads and writes. Unfortunately, the V+ performs poorly in our I/O performance test patterns, yet it sustains much better sequential write throughput than the SSDNow V.
Just like the regular V, the V+ arrives with 2.5”-to-3.5” mounting brackets. Kingston also bundles a 2.5” hard drive enclosure with a USB 2.0 interface. This isn’t state of the art anymore, but it allows upgrade users to remove their 2.5” hard drive from an existing notebook or laptop, install the SSDNow V+ into the mobile computer, and keep using the hard drive as a portable storage product in Kingston’s enclosure.
Toshiba’s architecture is much lower on power than the Toshiba/JMicron solution on the SSDNow V. The SSDNow V+ reaches an extremely low active idle power of only 0.06 W, which goes head-to-head with the generic Toshiba drive and Intel’s X25-M. The only other drives similar in idle power are the Crucial RealSSD C300 and Samsung’s new 470-series. The drive is also very low on power in our HD video playback (0.13 W) test and streaming reads (0.46 W).
As a result, the Kingston SSDNow V+’s power efficiency is excellent for streaming reads, delivering high throughout at minimum power requirements. We found this product to be a great option for upgrade users that don’t require maximum performance as well as notebook owners. Once again, performance users should read on.
Update: Just prior to this story going live, Kingston announced the V+-series' successor called the V+100. It employs a new controller in the same family as Toshiba's Daikoku. Again, we're looking at 32 nm NAND flash here. The updated drive will be covered in an upcoming comparison story.

2:00 AM - November 11, 2010 by Patrick Schmid and Achim Roos
Patriot’s Inferno uses the popular SandForce SF-1200 controller family, but the product was actually designed for the enthusiast mainstream. Patriot says that the drive balances power consumption and performance, and it also comes with a 2.5” to 3.5” installation bracket.
The red aluminum chassis provides a unique appearance, as all other SSDs typically come in black, grey, or silver. However, the innards are very typical: SandForce SF-1220 controller and Intel 64 Gb NAND memory chips. We found that the Inferno has lower minimum read and write rates than other SandForce SSDs. Its I/O performance is excellence, though, and only beaten occasionally by other SandForce SSDs or the Crucial RealSSD C300.
Inferno is also strong at 4 KB random writes, but it’s no match for some of the other SandForce drives or the RealSSD C300. PCMark Vantage application performance is strong, as well, and only a few drives, such as the Samsung 470-series, are noticeably faster.
Power consumption isn’t quite on par with other SandForce SSDs, but since power consumption never exceeded 1.33 W in our testing, we can confirm that Patriot’s mission to balance power and performance was successful.

While the previously-discussed SSDs all represent variations of existing controller designs, Samsung’s new 470-series can be called a new breed. You might also hear the term PM810 here and there, which is Samsung’s internal name for this product family. Samsung managed to improve its SSD line in all characteristics, including power consumption and performance, but the firm is staying with the SATA 3Gb/s interface, so you already know Samsung won’t overtake the throughput leader, Crucial’s RealSSD C300, in terms of data transfer rates.
The 470-series is a consumer product for the upper-mainstream and enthusiast market, and it comes with Samsung’s new toggle mode DDR NAND flash memory. Samsung adopted this approach in its latest flash memory, where it should help to improve SSD performance while keeping power consumption down. The results are impressive, but the technology doesn’t hit new records--yet.
This is a relatively slim, 7 mm z-height drive. Although this isn’t a very special feature, it may prove handy for compact notebook designs. Samsung offers 64 GB, 128 GB, and 256 GB capacities.
Our reviewed model is based on Samsung’s MAX controller (S3C29MAX), which is an eight-channel design utilizing 256 MB of cache memory along with 32-queue Native Command Queuing (NCQ) support. There are different enclosures depending on whether you get an OEM or a retail version. Our sample was the OEM variety, which can be opened easily. As you can see, the PCB is also small enough to fit into the 1.8” form factor. Expect identical performance there.
At a queue depth of 1 or up to 32, the 470-series is fairly strong on 4 KB random writes, drawing close to SandForce and the RealSSD C300 by Crucial. It beats everything else here and is also the fastest drive for sequential reads, right after the C300 and Intel’s X25-M G0. Everyone else is slightly behind. Watch out for the throughput benchmark. Our preferred h2benchw 3.6 almost exclusively works with zeroes, which favors the SandForce architecture. Still, h2benchw works well for examining minimum throughput and tracking performance drops across the test run.
The Samsung 470 reaches higher throughput and is stronger than most of the other SSDs, including the SandForce party, in our PCMark Vantage application tests. Additionally, we found it to be the best drive on sustained performance.
Lastly, the 470 series isn’t as low on power as the Toshiba drives or the Intel X25-M.

FamilyNobilityForce SeriesSSDNow V+
Model NumberN002CSSD-F160GBP2-BRKTSNVP325-S2/128GB
Capacity128 GB160 GB128 GB
ControllerIndilinx BarefootSandForce SF-1200Toshiba T6UG1XBG
Form Factor2.5"2.5"2.5"
InterfaceSATA 3Gb/sSATA 3Gb/sSATA 3Gb/s
Cache (MB)64 MBN/A128 MB
Height9.5 mm9.5 mm9.5 mm
MTBFN/A1,000,000 h1,000,000 h
Operating Temperature0-70° C0-70° C0-70° C
Specified Idle Power (low-power)N/A0.50 W0.15 W
Measured Idle Power (low-power)0.51 W0.52 W0.06 W
FamilySSDNow VInferno470-Series
Model NumberSNV425-S2/128GB  PI120GS25SSDRPM810
Capacity128 GB120 GB256 GB
ControllerToshiba TC58NCF618GBTSandForce SF-1200Samsung MAX
Form Factor2.5"2.5"2.5"
InterfaceSATA 3Gb/sSATA 3Gb/sSATA 3Gb/s
Cache (MB)64 MBN/A128 MB
Height9.5 mm9.5 mm9.5 mm
MTBF1,000,000 h1,500,000 h1,500,000 h
Operating Temperature0-70° C0-70° C0-70° C
Specified Idle Power (low-power)N/AN/AN/A
Measured Idle Power (low-power)1.36 W0.69 W0.16 W

Test Setup

System Hardware
CPUIntel Core i7-920 (45 nm, 2.66 GHz, 4 x 512 KB L2 Cache, 8 MB Shared L3 Cache)
Motherboard (LGA 1366)Supermicro X8SAX, Revision: 1.0, Chipset Intel X58 + ICH10R, BIOS: 1.0B
SATA controllerHighpoint Rocket 620, SATA 6 Gb/s
Memory3 x 1 GB DDR3-1333 Corsair CM3X1024-1333C9DHX
HDDSeagate NL35 400 GB, ST3400832NS, 7200 RPM, SATA 1.5Gb/s, 8 MB Cache
Power SupplyOCZ EliteXstream 800 W, OCZ800EXS-EU
Performance Measurementsh2benchw 3.13
PCMark Vantage
I/O PerformanceIOMeter 2008.08.18
Streaming Reads
Streaming Writes
4k Random Reads
4k Random Writes
System Software & Drivers
Operating SystemWindows 7 Ultimate x64

Access Time

There are access time differences, but they’re typically too small to matter in everyday operation.

I/O Performance

The performance differences using our database workload pattern are quite significant. The SandForce SSDs by G-Skill, RunCore, OWC, OCZ, Corsair, and Asax, as well as the Crucial’s RealSSD C300, present the best options for reading and writing many small data chunks. The Intel and Samsung SSDs are right in the middle, and some other products are obviously unsuitable, mostly because of latencies at write operations.

Differences in the file server test pattern are similar, but a bit less dramatic.

The Web server test does not include writes, which turns some of our results upside-down. The RealSSD C300 can play its throughput card, while Intel, Samsung, and all the SandForce devices come out shining, as well.

The workstation test involves lots of writes, again skewing toward the SandForce SSDs. Samsung and Intel don’t seem to be as strong, but look at the CrystalDiskMark results on the following pages for another angle of the performance evaluation.

Take a close look at this chart if you’re a road warrior that relies on notebook battery runtime. Intel, Kingston, Toshiba, Samsung, and Crucial clearly win.

Delivering peak throughput requires 0.42 W in a best case (Kingston SSDNow V 30 GB) or up to 2.44 W in a worst case. Take these results into consideration if you copy data frequenty.

The power consumption required by HD video playback illustrates how much power SSDs require under limited load scenarios. The difference between the best and the worst candidate isn’t much in absolute numbers, but in relative terms the gap is more than 10x!

Our efficiency results are somewhat distorted, as we have drives that require lots of power compared to others, while performance is all over the board.
When deciding on a drive for yourself, focus on a few performance favorites, then look at performance per watt. Toshiba is very low on power but also weak in some benchmarks. A RealSSD C300 consumes much more power to deliver its 350 MB/s peak, but it might be worth it. The decision depends on your requirements and applications.

Thanks to our work on this roundup, all of our future SSD tests will include CrystalDiskMark results, as these are more reliable when it comes to showing an SSD’s peak performance capabilities. The benchmark helped to show that Samsung’s new 470-series SSDs do well in maximizing performance. Our review unit uses SATA 3Gb/s instead of 6Gb/s and it doesn’t really outperform any of the other drives, but it shows consistency across all benchmarks and no severe weaknesses.
This has been an issue with other products. The throughput champ, Crucial’s RealSSD C300, remains the fastest drive in terms of megabytes per second, but it consumes more power and lags the SandForce drives in I/O performance. Intel has high I/O numbers and strong application performance, but it lacks write performance. And SandForce falls down on power consumption.

An SSD evaluation that provides you with a truly comprehensive picture on performance, power, and consistency won’t provide simple answers. Gone are the times when hard drives had a certain throughput and an access time. It’s extremely important for SSD testing to take workload types and popular application scenarios into account. A recommendation based on just a few benchmarks might be misleading because you can’t do justice to products without assuming all relevant viewing angles.
Having said that, the recommendations from our last SSD roundup are still valid. Architecture is what you should be looking for: Crucial/Marvel, Indilinx, Intel, Samsung, SandForce, or Toshiba?
You usually won’t regret buying an SSD with a SandForce SF-1200 controller. The balance between throughput, I/O performance, and application performance is still impressive. Corsair, G.Skill, Patriot, OCZ, Runcore, and others have suitable offerings. Look for best prices, warranty, and maybe an installation kit for your desktop PC if needed.
If you want to maximize throughput, you have no alternative but to purchase Crucial’s RealSSD C300. Mobile users can only get rock bottom power consumption if they stay with Toshiba hardware, which isn’t the fastest. Intel SSDs offer a good compromise between power and performance, but you have to be aware of their limited write performance.
Samsung’s 470-series only shows marginal weaknesses across our benchmark suite. If Samsung were to price the drive more aggressively, it would be a more compelling option.

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