Original Link: https://www.anandtech.com/show/10833/the-samsung-960-evo-1tb-review



Last month the Samsung 960 Pro broke most of the performance records for a consumer SSD and often by a surprisingly large margin. But as impressive as it was to see the combination of high capacity and high performance in such a small package, the 2TB 960 Pro we reviewed is too expensive to be a realistic option for most enthusiasts.

Enter the Samsung 960 EVO. With the same powerful SSD controller used on the 960 Pro but much cheaper TLC 3D NAND, the 960 EVO is far more affordable but promises similar peak performance. Despite being Samsung's low-end M.2 PCIe option, the 960 EVO is aiming to outperform last year's 950 Pro and the current flagship PCIe SSDs from Samsung's competitors.

Samsung 960 EVO Specifications Comparison
  960 EVO
1TB
960 EVO 500GB 960 EVO 250GB 950 PRO
512GB
950 PRO
256GB
Form Factor single-sided
M.2 2280
single-sided
M.2 2280
Controller Samsung Polaris Samsung UBX
Interface PCIe 3.0 x4
NAND Samsung 48-layer
256Gb TLC V-NAND
Samsung 32-layer
128Gbit MLC V-NAND
SLC Cache Size 42GB 22 GB 13GB N/A
Sequential Read 3200 MB/s 3200 MB/s 3200 MB/s 2500 MB/s 2200 MB/s
Sequential Write (SLC Cache) 1900 MB/s 1800 MB/s 1500 MB/s 1500 MB/s 900 MB/s
Sequential Write (sustained) 1200 MB/s 600 MB/s 300 MB/s N/A N/A
4KB Random Read (QD32) 380k IOPS 330k IOPS 330k IOPS 300k IOPS 270k IOPS
4KB Random Write (QD32) 360k IOPS 330k IOPS 300k IOPS 110k IOPS 85k IOPS
Power 5.7W
(average)
5.4W
(average)
5.3W
(average)
7.0W (burst)
5.7W (average)
1.7W (idle)
6.4W (burst)
5.1 (average)
1.7W (idle)
Endurance 400TB 200TB 100TB 400TB 200TB
Warranty 3 Year 5 Year
Launch MSRP $479.99 $249.99 $129.88 $350 $200

The 960 EVO is not the first M.2 PCIe SSD to use TLC NAND. Samsung's OEM product line has the PM951 and PM961, using the same controllers as the 950 Pro and 960 Pro respectively. Intel has also shipped the 600p as their first 3D NAND SSD for the consumer market, but the Silicon Motion controller it uses is a far cry from the monster of a controller used in their flagship SSD 750.

As a more cost-focused product than the 960 Pro, the 960 EVO has a lower range of capacity options. With a maximum capacity of 1TB, the 960 EVO does not need to use the controller+DRAM package on package stacking that was necessary for the 2TB 960 Pro to be a single-sided M.2 module. As is normal for Samsung's EVO lines, the usable capacities are a bit smaller, with the 1TB EVO being 1000GB instead of 1024GB.

Some of the extra spare area reserved is used for the SLC write cache, which Samsung is now branding as 'Intelligent TurboWrite'. Where the 850 EVO's TurboWrite cache was 3-12GB depending on drive capacity, the 960 EVO has 4-6GB of guaranteed cache plus 9-36GB of dynamic cache when the drive has sufficient free space. Having a cache that is several times larger will greatly expand the range of workloads that can fit in the cache, and will help the 960 EVO make the best of its PCIe 3.0 x4 interface that is much faster than SATA.


Spot the copper-backed heat spreader label underneath

The 960 EVO includes all of the thermal management measures of the 960 Pro, including the copper-backed heat spreading label, a very power-efficient controller and a well-tuned thermal throttling implementation. TLC NAND has been shown to be, in general, slower and more power-hungry than MLC NAND so the 960 EVO is more susceptible to thermal throttling than the 960 Pro, but Samsung claims it is still less of a problem than it was for the 950 Pro, which means that virtually all real-world usage scenarios will not trigger throttling.

The warranty period for the 960 EVO is three years instead of the five enjoyed by the 850 EVO and both generations of MLC-based PCIe SSDs. The drive write endurance rating is also only half that of the 960 and 950 Pros, but 100TB for a 250GB drive is a sufficient amount.

For this review, Samsung provided an advance copy of their new NVMe driver version 2.0 to support the 960 Pro and 960 EVO as well as the 950 Pro. The 960 EVO was tested with Samsung's driver and the 960 Pro was also re-tested using this driver instead of Microsoft's driver built in to Windows. The results for the 950 Pro are still from version 1.0 of Samsung's NVMe driver. The next major release of Samsung's Magician software is still not quite ready, so exploration of encryption capabilities and other new features will have to wait. Samsung expects to release Magician 5 by the end of the month.

Samsung provided a 250GB 960 EVO and a 1TB 960 EVO for this review. The 250GB 960 EVO failed relatively early in the testing process, after completing a few of the IOmeter tests and while it was about 10% of the way through being filled to prepare for the next test. We are working with Samsung to determine the cause of the failure but due to the short time available we have not been able to reach a conclusion as of press time. These review units are technically preproduction samples and thus their failure rates are probably not indicative of the mass-market reliability. SSD deaths are nothing new at AnandTech, and in the past some of them have been our fault rather than due to defective goods. But regardless of what triggered this failure, there is a bright side: our testing usually doesn't tell us anything about the end-of-life behavior of SSDs. If our 250GB 960 EVO has indeed failed unrecoverably, it did so gracefully: the drive entered a read-only state during the fill process, which caused IOmeter to hang, but the data already written is still accessible and the drive still reports its SMART indicators and error codes. Aside from refusing to accept write or secure erase commands, the only symptom of the drive's failure is higher than normal idle power consumption.

For this review, the 1TB 960 EVO will be compared to the 2TB 960 Pro, last year's 950 Pro, and the current flagship NVMe drives from Intel and Toshiba (OCZ). For context, results from several 1TB SATA SSDs are also included. As always, our Bench tool can be used to compare against any other drive in our database of test results.

AnandTech 2015 SSD Test System
CPU Intel Core i7-4770K running at 3.5GHz
(Turbo & EIST enabled, C-states disabled)
Motherboard ASUS Z97 Pro (BIOS 2701)
Chipset Intel Z97
Memory Corsair Vengeance DDR3-1866 2x8GB (9-10-9-27 2T)
Graphics Intel HD Graphics 4600
Desktop Resolution 1920 x 1200
OS Windows 8.1 x64


Performance Consistency

Our performance consistency test explores the extent to which a drive can reliably sustain performance during a long-duration random write test. Specifications for consumer drives typically list peak performance numbers only attainable in ideal conditions. The performance in a worst-case scenario can be drastically different as over the course of a long test drives can run out of spare area, have to start performing garbage collection, and sometimes even reach power or thermal limits.

In addition to an overall decline in performance, a long test can show patterns in how performance varies on shorter timescales. Some drives will exhibit very little variance in performance from second to second, while others will show massive drops in performance during each garbage collection cycle but otherwise maintain good performance, and others show constantly wide variance. If a drive periodically slows to hard drive levels of performance, it may feel slow to use even if its overall average performance is very high.

To maximally stress the drive's controller and force it to perform garbage collection and wear leveling, this test conducts 4kB random writes with a queue depth of 32. The drive is filled before the start of the test, and the test duration is one hour. Any spare area will be exhausted early in the test and by the end of the hour even the largest drives with the most overprovisioning will have reached a steady state. We use the last 400 seconds of the test to score the drive both on steady-state average writes per second and on its performance divided by the standard deviation.

Steady-State 4KB Random Write Performance

The 960 EVO's steady state random write speed is not quite as fast as the 960 Pro, but it's in the same league and much faster than most consumer SSDs.

Steady-State 4KB Random Write Consistency

The 960 EVO sets a new record for combining high performance with consistency. It's a bit slower than the 960 Pro, but less variable.

IOPS over time
Default
25% Over-Provisioning

Highly consistent performance is a good thing, but it makes for a boring graph. The transitions from peak to sustained performance modes look the same for both the 960 Pro and the 960 EVO.

Steady-State IOPS over time
Default
25% Over-Provisioning

The 960 EVO responds to extra overprovisioning with even more consistent (and high) performance.



AnandTech Storage Bench - The Destroyer

The Destroyer is an extremely long test replicating the access patterns of very IO-intensive desktop usage. A detailed breakdown can be found in this article. Like real-world usage and unlike our Iometer tests, the drives do get the occasional break that allows for some background garbage collection and flushing caches, but those idle times are limited to 25ms so that it doesn't take all week to run the test.

We quantify performance on this test by reporting the drive's average data throughput, a few data points about its latency, and the total energy used by the drive over the course of the test.

AnandTech Storage Bench - The Destroyer (Data Rate)

The 960 EVO is substantially slower than both the 950 Pro and 960 Pro, but the 960 EVO is faster than the flagship SSDs from Toshiba and Intel.

AnandTech Storage Bench - The Destroyer (Latency)

The 960 EVO delivers average service times on par with other high-end PCIe SSDs, and is still slightly faster than any non-Samsung drive.

AnandTech Storage Bench - The Destroyer (Latency)AnandTech Storage Bench - The Destroyer (Latency)

In the frequency of high-latency outliers, the 960 EVO is surpassed only by Samsung's 950 Pro and 960 Pro.

AnandTech Storage Bench - The Destroyer (Power)

Despite using TLC NAND, the 960 EVO manages comparable power efficiency to the 960 Pro, putting it ahead of the fastest SATA drives but still drawing substantially more power than the most efficient SATA SSDs.



AnandTech Storage Bench - Heavy

Our Heavy storage benchmark is proportionally more write-heavy than The Destroyer, but much shorter overall. The total writes in the Heavy test aren't enough to fill the drive, so performance never drops down to steady state. This test is far more representative of a power user's day to day usage, and is heavily influenced by the drive's peak performance. The Heavy workload test details can be found here.

AnandTech Storage Bench - Heavy (Data Rate)

The 960 EVO's average data rates on the Heavy test are slower than the 950 Pro and 960 Pro, but on par with the OCZ RD400 and faster than the Intel 750.

AnandTech Storage Bench - Heavy (Latency)

The 960 EVO takes third place for average service times, providing lower latency than the smallest 950 Pro despite slower overall data rates. In comparison to SATA SSDs, the latency differences are all pretty minor.

AnandTech Storage Bench - Heavy (Latency)

Like the 960 Pro, the 960 EVO oddly has slightly fewer high-latency outliers when this test is run on a full drive instead of a freshly-erased drive. In spite of this quirk of the drive's garbage collection routines, both drives have well-controlled latency.

AnandTech Storage Bench - Heavy (Power)

The 960 EVO's power efficiency on the Heavy test is virtually the same as the 960 Pro and the 950 Pro, and not significantly worse than the fastest SATA drives.



AnandTech Storage Bench - Light

Our Light storage test has relatively more sequential accesses and lower queue depths than The Destroyer or the Heavy test, and it's by far the shortest test overall. It's based largely on applications that aren't highly dependent on storage performance, so this is a test more of application launch times and file load times. This test can be seen as the sum of all the little delays in daily usage, but with the idle times trimmed to 25ms it takes less than half an hour to run. Details of the Light test can be found here.

AnandTech Storage Bench - Light (Data Rate)

As with the previous ATSB tests, the 960 EVO can't quite keep pace with Samsung's MLC-based 950 Pro and 960 Pro SSDs, but it is slightly faster than the OCZ RD400. On this test the 960 EVO suffers relatively more from a full drive, where it falls behind the RD400.

AnandTech Storage Bench - Light (Latency)

Average service times are slightly slower for the 960 EVO than Samsung's other PCIe SSDs, and the competing PCIe SSDs are a step further behind.

AnandTech Storage Bench - Light (Latency)

The 960 EVO is tied for first place with minimal high-latency outliers, but all of the PCIe SSDs are much better than the SATA drives.

AnandTech Storage Bench - Light (Power)

Once again the 960 EVO's power efficiency is about the same as Samsung's other drives, showing that its higher instantaneous power draw than SATA drives is compensated by it completing the test quicker.



Random Read Performance

The random read test requests 4kB blocks and tests queue depths ranging from 1 to 32. The queue depth is doubled every three minutes, for a total test duration of 18 minutes. The test spans the entire drive, which is filled before the test starts. The primary score we report is an average of performances at queue depths 1, 2 and 4, as client usage typically consists mostly of low queue depth operations.

Iometer - 4KB Random Read

It is unsurprising to see that the TLC-based 960 EVO has slower random read speeds than the MLC-based 950 Pro and 960 Pro, but the 960 EVO still manages to be faster than all the non-Samsung drives.

Iometer - 4KB Random Read (Power)

The 960 EVO's power consumption is essentially the same as Samsung's other drives, which puts it at an efficiency disadvantage to their MLC PCIe SSDs but more efficient than all the lower-performing drives.

As with Samsung's other SSDs, random read speed scales with queue depth until hitting a limit at QD16.

Random Write Performance

The random write test writes 4kB blocks and tests queue depths ranging from 1 to 32. The queue depth is doubled every three minutes, for a total test duration of 18 minutes. The test is limited to a 16GB portion of the drive, and the drive is empty save for the 16GB test file. The primary score we report is an average of performances at queue depths 1, 2 and 4, as client usage typically consists mostly of low queue depth operations.

Iometer - 4KB Random Write

The Samsung 960 EVO's random write speed is essentially tied with the 960 Pro and the OCZ RD400A, while the Intel 750 holds on to a comfortable lead.

Iometer - 4KB Random Write (Power)

The 960 EVO is not as power efficient as the 960 Pro, but it is still far better than everything else.

The scaling behavior of the 960 EVO is essentially the same as the 960 Pro: full performance is reached at QD4, and there's no indication of any severe thermal throttling.



Sequential Read Performance

The sequential read test requests 128kB blocks and tests queue depths ranging from 1 to 32. The queue depth is doubled every three minutes, for a total test duration of 18 minutes. The test spans the entire drive, and the drive is filled before the test begins. The primary score we report is an average of performances at queue depths 1, 2 and 4, as client usage typically consists mostly of low queue depth operations.

Iometer - 128KB Sequential Read

The 960 EVO provides slightly higher sustained sequential read speeds than the 960 Pro in a test where both are largely thermally limited. No other SSD comes close to offering this level of performance at low queue depths.

Iometer - 128KB Sequential Read (Power)

With power consumption slightly lower than the 960 Pro, the 960 EVO actually manages to set an efficiency record.

The competing drives that have large heatsinks can provide better performance at higher queue depths, but within the constraints of the M.2 form factor Samsung has a huge advantage.

Sequential Write Performance

The sequential write test writes 128kB blocks and tests queue depths ranging from 1 to 32. The queue depth is doubled every three minutes, for a total test duration of 18 minutes. The test spans the entire drive, and the drive is filled before the test begins. The primary score we report is an average of performances at queue depths 1, 2 and 4, as client usage typically consists mostly of low queue depth operations.

Iometer - 128KB Sequential Write

The sustained sequential write speed of the 960 EVO is far slower than the 960 Pro and several of the better-cooled competitors, but the 960 EVO is actually slightly faster than last year's 950 Pro.

Iometer - 128KB Sequential Write (Power)

The 960 EVO doesn't break any records for power efficiency, but only because the 960 Pro exists. The MLC-based competition is less efficient than the TLC-based 960 EVO.

For almost all of the sequential write speed test, the 960 EVO is thermally limited, but it is clearly able to do much more within that limit than the 950 Pro or OCZ RD400 could.



Mixed Random Read/Write Performance

The mixed random I/O benchmark starts with a pure read test and gradually increases the proportion of writes, finishing with pure writes. The queue depth is 3 for the entire test and each subtest lasts for 3 minutes, for a total test duration of 18 minutes. As with the pure random write test, this test is restricted to a 16GB span of the drive, which is empty save for the 16GB test file.

Iometer - Mixed 4KB Random Read/Write

The 960 EVO is essentially tied for second place with the OCZ RD400 and significantly behind the 960 Pro in overall performance on mixed random I/O.

Iometer - Mixed 4KB Random Read/Write (Power)

The 960 EVO's power efficiency on this test is not great, but it is a big improvement over last year's 950 Pro.

The 960 EVO's high performance score comes primarily from its great performance in the pure write final phase of the test. Throughout the rest of the test, the 960 EVO is not as fast as the 950 Pro.

Mixed Sequential Read/Write Performance

The mixed sequential access test covers the entire span of the drive and uses a queue depth of one. It starts with a pure read test and gradually increases the proportion of writes, finishing with pure writes. Each subtest lasts for 3 minutes, for a total test duration of 18 minutes. The drive is filled before the test starts.

Iometer - Mixed 128KB Sequential Read/Write

The 960 EVO's mixed sequential I/O performance is the second-fastest among M.2 SSDs and third place overall. Performance is modestly improved over the 950 Pro.

Iometer - Mixed 128KB Sequential Read/Write (Power)

The 960 EVO's power efficiency is better than most PCIe SSDs, but still well behind the 960 Pro.

The 960 EVO's performance in the pure read first phase of the test is great, but its performance with an 80/20 mix is much worse than the 950 Pro or OCZ RD400. The worst-case performance is also not as good as the RD400 or 960 Pro.



ATTO

ATTO's Disk Benchmark is a quick and easy freeware tool to measure drive performance across various transfer sizes.

ATTO Performance

By the end of the test, the 960 EVO and 960 Pro are performing identically. The 960 EVO takes longer to get up to full read speed, and the 960 Pro turns in some slightly better write speeds before thermal throttling levels things out.

AS-SSD

AS-SSD is another quick and free benchmark tool. It uses incompressible data for all of its tests, making it an easy way to keep an eye on which drives are relying on transparent data compression. The short duration of the test makes it a decent indicator of peak drive performance.

Incompressible Sequential Read Performance

Incompressible Sequential Write Performance

Both AS-SSD sequential tests show that the 960 EVO's peak performance really is second only to the 960 Pro, even if in longer tests some other models are able to outperform the 960 EVO.

Idle Power Consumption

Since the ATSB tests based on real-world usage cut idle times short to 25ms, their power consumption scores paint an inaccurate picture of the relative suitability of drives for mobile use. During real-world client use, a solid state drive will spend far more time idle than actively processing commands. Our testbed doesn't support the deepest DevSlp power saving mode that SATA drives can implement, but we can measure the power usage in the intermediate slumber state where both the host and device ends of the SATA link enter a low-power state and the drive is free to engage its internal power savings measures.

We also report the drive's idle power consumption while the SATA link is active and not in any power saving state. Drives are required to be able to wake from the slumber state in under 10 milliseconds, but that still leaves plenty of room for them to add latency to a burst of I/O. Because of this, many desktops default to either not using SATA Aggressive Link Power Management (ALPM) at all or to only enable it partially without making use of the device-initiated power management (DIPM) capability. Additionally, SATA Hot-Swap is incompatible with the use of DIPM, so our SSD testbed usually has DIPM turned off during performance testing.

Idle Power Consumption
Active Idle Power Consumption (No LPM)

Idle power for the 960 EVO is the same as for the 960 Pro. Our usual testbed configuration does not engage any explicit power saving modes so the 960 EVO idles at 1.2 W where most SATA drives will draw much less than 1W. On systems that make use of NVMe power saving capabilities, idle power will be only a few times higher than the best SATA drives, and this is without making full use of PCIe link power management.



Final Words

If the Samsung 960 Pro didn't exist and anybody other than Samsung released the 960 EVO, it would be a credible flagship product for today's SSD market. It is clearly faster than the Intel 750 everywhere that matters. It is on par with the OCZ RD400 on real-world workloads. It is generally slightly slower than last year's 950 Pro, but does improve on some of the 950's more acute weaknesses. It does all of this while being more power efficient under load, and the 960 EVO carries an MSRP that is lower than the current retail prices of other high-end PCIe SSDs.

Of course, the 960 Pro does in fact exist and is being released alongside the 960 EVO. It looks like the two product lines will occupy similar positions within the PCIe SSD market that the 850 Pro and 850 EVO have within the SATA SSD market. The 960 Pro will hold the indisputable performance crown, but the 960 EVO will be the more popular product. The EVOs are not low-end drives by price or performance, and while they may not be the most affordable mid-range options, they're solid performers that benefit greatly from using the same high-end SSD controllers as their Pro counterparts. Unlike Intel's 600p budget TLC PCIe SSD, the 960 EVO always manages to be a big upgrade over any SATA SSD.

  128GB 250-256GB 400-512GB 1TB 2TB
Samsung 960 EVO (MSRP)   $129.88 (52¢/GB) $249.99 (50¢/GB) $479.99 (48¢/GB)  
Samsung 960 Pro (MSRP)     $329.99 (64¢/GB) $629.99 (62¢/GB) $1299.99 (63¢/GB)
Samsung 950 Pro   $185.50 (72¢/GB) $314.99 (62¢/GB)    
Toshiba OCZ RD400A $139.99 (109¢/GB) $215.16 (84¢/GB) $257.20 (50¢/GB) $729.99 (71¢/GB)  
Toshiba OCZ RD400 M.2 $119.99 (94¢/GB) $149.99 (59¢/GB) $299.98 (59¢/GB) $709.99 (69¢/GB)  
Intel SSD 600p $60.00 (47¢/GB) $94.45 (37¢/GB) $167.30 (33¢/GB) $380.54 (37¢/GB)  
Intel SSD 750     $319.99 (80¢/GB) $749.99 (62¢/GB)  
Plextor M8Pe $74.99 (59¢/GB) $114.99 (45¢/GB) $189.99 (37¢/GB) $414.99 (41¢/GB)  

The price and performance of the 960 EVO will make anything more expensive a very tough sell. The only advantage a drive like the the RD400 has is in its warranty period and endurance rating: the 960 EVO's three years and 0.3 DWPD are not exactly premium specifications, but neither are they low enough to cause much concern. The 960 Pro will offer a 2TB option and even higher performance, but those are expensive luxuries. The 960 EVO will be undercutting most of the PCIe SSD market with "good enough" performance.

The Plextor M8Pe is currently in the SSD testbed where we don't expect it to surpass the OCZ RD400 or Samsung 960 EVO, but matching their performance would likely make the M8Pe the clear favorite over the 960 EVO. The one thing holding back the 960 EVO from becoming the default product recommendation among PCIe SSDs is the fact that some MLC-based drives will be competing with the 960 EVO on price and may also come close in performance. 

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