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Original Link: https://www.anandtech.com/show/10741/the-western-digital-blue-1tb-ssd-review



Five months after completing its acquisition of SanDisk, Western Digital is introducing SSDs under the WD brand for the consumer market. The WD Blue is the mainstream SATA offering and is derived from the SanDisk X400. While not exactly the first Western Digital SSD in blue, the WD Blue is the beginning of a new era for the WD brand and is an acknowledgment that SSDs are now mainstream consumer products that exist alongside or displace hard drives instead of just occupying a high-end niche.

The SanDisk X400 was announced at the beginning of this year as the new flagship of SanDisk's business/OEM client SSD family. When we reviewed it in May we were pleasantly surprised to find that it raised the bar for the performance and power efficiency of planar TLC SSDs and was a credible mid-range drive, not just an entry-level budget-oriented product. The WD Blue SSD uses the same hardware platform as the SanDisk X400, but with some changes to the firmware. Most notably, the WD Blue reserves a bit more spare area and thus has capacities of 250GB, 500GB and 1000GB where the X400 has capacities of 128GB–1024GB. There are minor differences to the performance specifications and the WD Blue has only a three year warranty compared to the X400's five years. (Though still better than the two year warranty carried by the current WD Blue hard drives.)

Western Digital WD Blue Specifications
Capacity 250GB 500GB 1000GB
Form Factor 2.5" 7mm SATA or M.2 2280 SATA
Controller Marvell 88SS1074
NAND SanDisk 15nm TLC
Sequential Read 540 MB/s 545 MB/s 545 MB/s
Sequential Write 500 MB/s 525 MB/s 525 MB/s
4KB Random Read 97k IOPS 100k IOPS 100k IOPS
4KB Random Write 79k IOPS 80k IOPS 80k IOPS
Average Power 70 mW
Max Power 4.4 W
Encryption No
Endurance (TBW) 100 TB 200 TB 400 TB
Warranty Three years
MSRP $79.99 $139.99 $299.99

All capacities of the WD Blue are available in either the 2.5" SATA form factor or as M.2 2280 cards. This continues the trend of recent mainstream SATA SSDs placing M.2 on an equal footing with the 2.5" form factor.

As a result of the increased spare area, the WD Blue has a higher write endurance rating than the SanDisk X400 and one of the highest endurance ratings of any TLC SSD. It even exceeds the rating on some capacities of the Samsung 850 Pro that comes with a 10 year warranty. Western Digital is pitching the WD Blue as suitable for heavy workloads, and even if its performance falls short of the best SATA drives it should last a very long time even when subject to a write-intensive workload.

SSD Endurance Specifications Comparison
Capacity 240-256GB 480-512GB 960-1024GB
WD Blue 100 TBW 200 TBW 400 TBW
SanDisk X400 80 TBW 160 TBW 320 TBW
OCZ Trion 150 60 TBW 120 TBW 240 TBW
OCZ VX500 148 TBW 296 TBW 592 TBW
Samsung 850 EVO 75 TBW 150 TBW 150 TBW
Samsung 850 Pro 150 TBW 300 TBW 300 TBW

The construction of the WD Blue carries over the same metal case and plastic lid that SanDisk has been using for years. Inside our 1TB sample we find the same single-sided PCB as in the X400 and the thermal pad that covers nearly every component. The NAND is arranged in eight packages of 128GB each, while the Micron DRAM is split across two packages.

For this review the 1TB WD Blue will be compared against most of the other 1TB-class SATA drives we have tested. The current competition in the marketplace consists primarily of the preceding SanDisk X400, cheaper planar TLC SSDs such as the OCZ Trion 150, MLC SSDs that are mostly significantly more expensive, and 3D TLC SSDs such as the Samsung 850 EVO and Crucial MX300. Note that while we have already reviewed the 750GB Crucial MX300, in this review we are comparing against the 1050GB MX300 that will be covered by an upcoming review of the wider range of MX300 capacities that are now available.

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

With a slight increase in out of the box overprovisioning, it is unsurprising to see the WD Blue improve on the SanDisk X400's steady-state random write performance. The WD Blue overtakes the OCZ Trion 150 as the fastest planar TLC NAND SSD, but doesn't catch up to the MLC or 3D TLC drives.

Steady-State 4KB Random Write Consistency

The WD Blue has slightly worse performance consistency than the X400, but not low enough to be cause for concern.

IOPS over time
Default
25% Over-Provisioning

Before reaching steady state, the WD Blue hovers between 20k and 30k IOPS, a significant improvement over the X400. Several other competitors have higher peak performance, but are either less consistent during the early phase of the test or don't last as long before dropping to steady state.

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

Upon reaching steady state, the WD Blue varies from roughly 2500 IOPS to 5000 IOPS, with short bursts of slightly higher performance. With extra overprovisioning the base performance of the WD Blue doesn't change but the upper limit of its normal band of performance increases to around 10k IOPS and the peaks reach 25k.



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 WD Blue fails to keep up with the competition on The Destroyer, trailing behind everything except the Crucial BX200. Where the SanDisk X400 was one of the fastest TLC SSDs, the WD Blue is merely acceptable.

AnandTech Storage Bench - The Destroyer (Latency)

The average service time of the WD Blue is only slightly worse than the SanDisk X400, and still clearly better than the OCZ Trion 150. This suggests that the WD Blue's lower average data rate is due to it being uniformly a bit slower, and that it isn't experiencing any severe stalling.

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

The WD Blue does not suffer from any more high-latency outliers than other TLC drives at the 100ms threshold, but at the 10ms threshold it is worse than average where the X400 exceeded expectations.

AnandTech Storage Bench - The Destroyer (Power)

The WD Blue thankfully shows no regression in power efficiency and falls in the second tier of drives with energy usage, on par with the SanDisk X400.



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 WD Blue is tied with the OCZ Trion 150 for average data rate on the Heavy test, where the SanDisk X400 had a substantial advantage that put it close to MLC drives.

AnandTech Storage Bench - Heavy (Latency)

As with The Destroyer, the WD Blue only has slightly higher average latency than the X400 and is not as slow as the Trion 150. Additionally, the average latency on a full drive beats competitors like the OCZ VX500 and Crucial MX300 that suffer disproportionately when their SLC caches are exhausted.

AnandTech Storage Bench - Heavy (Latency)

The number of high-latency outliers makes it obvious that the WD Blue is a TLC drive, but also makes it clear that the drive degrades gracefully under a heavier load rather than falling apart.

AnandTech Storage Bench - Heavy (Power)

The WD Blue is slightly more power efficient on the Heavy test than the X400, and both drives have better than average power consumption.



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)

The WD Blue's average data rate on the Light test is surprisingly slow and barely faster than the Crucial BX200. It appears that the WD Blue cannot deliver very fast burst performance even though it performs reasonably well under a sustained load.

AnandTech Storage Bench - Light (Latency)

While the WD Blue only barely beat the Crucial BX200 on average data rate, it clearly wins on average service time. The WD Blue's empty drive average latency is substantially higher than most of the competition, but its full drive performance stands out less.

AnandTech Storage Bench - Light (Latency)

The number of high-latency outliers experienced by the WD Blue on the Light test is much higher than most of the competition, but also less than half what the Crucial BX200 suffered.

AnandTech Storage Bench - Light (Power)

Power consumption is once again a highlight of the WD Blue, with above average performance that is slightly better than the SanDisk X400.



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

The WD Blue's random read speed is a bit slower than the X400 but the difference is not big enough to change the rankings and it is still above average.

Iometer - 4KB Random Read (Power)

The WD Blue draws slightly less power than the SanDisk X400, which is enough for it to retain efficiency that is good by the standards of planar TLC SSDs.

The WD Blue's random read performance scales well with increasing queue depth, eventually reaching a maximum that is almost as high as the top SATA drives. The performance at QD16 is also notably better than most budget SSDs.

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 SanDisk X400 went a long way toward closing the gap in random write performance between TLC and MLC drives, but a substantial gap still remained. The WD Blue comes in just shy of the X400 but is much faster than the OCZ Trion 150.

Iometer - 4KB Random Write (Power)

The WD Blue doesn't set any overall record for power efficiency, but it does slightly improve on the X400's efficiency and raises the bar for planar TLC.

The WD Blue shows minimal random write performance scaling with queue depth, increasing from QD1 to QD2 but remaining constant thereafter.



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

While the SanDisk X400 tied the best MLC SSDs for sequential read speed, the WD Blue is merely average overall.

Iometer - 128KB Sequential Read (Power)

The WD Blue draws slightly less power than the X400, but given the size of the performance regression the WD Blue is actually less efficient for once.

The WD Blue seems to hit a performance plateau that is a bit shy of saturating the SATA link, and then it slows down at the highest queue depths.

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 WD Blue has a faster sequential write speed than the X400, but doesn't quite catch up to the OCZ Trion 150. Most MLC and 3D TLC drives are significantly faster than the planar TLC drives.

Iometer - 128KB Sequential Write (Power)

The WD Blue draws more power than the SanDisk X400 during the sequential write test, but it is justified by the improved performance. Efficiency is still only good by planar TLC standards.

The WD Blue's sequential read speed is constant across all queue depths, without even an increase from QD1 to QD2.



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

Like the SanDisk X400, the WD Blue performs better on the mixed random I/O test than competing planar TLC drives and about the same as the slowest MLC drives.

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

The WD Blue once again slightly raises the efficiency standards for planar TLC, but is still nowhere near as efficient as 3D TLC or MLC.

The WD Blue starts the mixed random I/O test with a pretty good random read speed, but performance declines as writes are added to the mix until near the end of the test, where the jump in the last segment of the test is not as large as what most drives experience.

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 WD Blue performs above average for a planar TLC SSD on the mixed sequential I/O test, but is not competitive with MLC or 3D TLC.

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

In absolute terms the WD Blue has pretty low power draw on this test, but the efficiency is not close to setting a record.

The WD Blue's U-shaped performance curve across this test is fairly typical, but the dropoff at the beginning is relatively steep and the minimum is a bit on the low side.



ATTO

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

ATTO Performance

The WD Blue shows slightly better write speeds on the ATTO test than the SanDisk X400, but both fade a bit in read speed toward the end of the test.

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 PerformanceIncompressible Sequential Write Performance

The AS-SSD test seldom shows large differences in performance, and the WD Blue performs almost identically to the X400. The write speed is still a bit on the low side.

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 (HIPM+DIPM)
Active Idle Power Consumption (No ALPM)

The WD Blue uses a few milliwatts more at idle than the X400. In the slumber state this is not a problem and the WD Blue's power draw is about average. The active idle power draw is a bit on the high side given that the MX300 draws about two thirds what the WD Blue draws when both drives use the same controller and DRAM.



Final Words

When it was first announced at the beginning of this year, the SanDisk X400 was a good value. It raised the bar for planar TLC performance and carried a reasonable mid-range price. The X400 offered OEMs a TCG Opal-compliant self encrypting drive option and was the first single-sided 1TB M.2 SSD.

The WD Blue follows in the footsteps of the SanDisk X400 and doesn't break any new ground. The hardware is essentially identical, but the firmware has been re-tuned. The WD Blue trades some capacity for an increased write endurance rating that is above average for a mainstream SATA SSD. The extra overprovisioning allows for improved sustained random write performance, one of the few benchmarks where the X400 was not the fastest planar TLC drive. Unfortunately, the WD Blue is slower than the X400 on most other tests and is not able to secure a claim to being the fastest budget SSD, though it does offer decent well-rounded performance with no major shortcomings. In spite of the increased endurance rating, the WD Blue only comes with a three year warranty compared to the five year warranty offered on the X400.

The WD Blue does manage to push the limits of planar TLC power efficiency, but only incrementally. In comparison to the radical improvement offered by Micron's 3D TLC in the Crucial MX300, the WD Blue's progress is insignificant.

SATA SSD Price Comparison
Capacity 240-256GB 480-512GB 960-1024GB
WD Blue (MSRP) $79.99 $139.99 $299.99
SanDisk X400 $79.99 $135.19 $248.99
Crucial MX300 $69.98 $119.99 $247.40
OCZ Trion 150 $65.74 $112.99 $226.00
OCZ VX500 $96.99 $154.99 $334.99
Samsung 850 EVO $99.99 $157.30 $306.07

The most important difference between the WD Blue and the SanDisk X400 is the fact that the WD Blue is launching into a very different market. Planar TLC NAND is no longer the only option for budget SSDs as Micron's 3D TLC is now shipping in volume and is substantially cheaper than Samsung's 3D TLC in the 850 EVO. The Crucial MX300 based on Micron's 3D TLC is faster and substantially more power efficient than planar TLC SSDs including both the SanDisk X400 and the WD Blue.

However the market doesn't seem to have fully adjusted to this situation. The SanDisk X400 is currently more expensive than the Crucial MX300 while only offering a longer warranty period to justify the premium. More entry-level TLC drives like the OCZ Trion 150 are barely cheaper than the MX300. To compete against the Crucial MX300 and other 3D TLC drives that are coming to market, the WD Blue will have to be priced far below its starting MSRP, which seems to have been set in consideration of only the planar TLC competition. Micron's 3D TLC is driving down prices and if Western Digital can't make the WD Blue even cheaper, it will not be able to secure a place in the crowded SSD market.  

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