Three Terabyte capacity in a 4-platter drive and 750GB/disc density is excellent, but the 2 TB model in a drive with one less disc might prove to be even better for noise and power. We examine samples of the latest WD Caviar Green models along with an earlier 2 TB 4-platter AV-optimized Green.
Dec 7, 2010 by Mike Chin
| Products | WD Caviar Green 3TB, 2TB WD20EARS & 2TB WD20EVDS |
| Sample Supplier | |
| Street Price | US$250; US$100 |
Western Digital’s announcement a few weeks ago of its new 3TB Caviar Green drive brought many issues in the storage sector into sharp relief. A 3TB HDD by itself is not unique. Seagate’s 3TB FreeAgent external hard drive has been available since the end of June. That begs the question of why Seagate has still not released the bare 3TB drive.
The answer is contained in a WD document entitled Large Capacity Drives (PDF), which addresses the 2.19 TB barrier imposed by legacy BIOS and the Master Boot Record (MBR) partition table scheme. This document is worth a read if you’re looking for a more complete understanding of the 2.19 TB limitation. It’s a complicated issue that we posted news on some weeks ago (Sandy Bridge, Bulldozer and UEFI); in a nutshell, the only consistent way to access more than 2.19 TB in a single drive with most current PCs is to use it as a secondary, non-boot, storage drive. Widespead adoption of 64-bit Windows and the new Unified Extensible Firmware Interface (UEFI) — replacing the motherboard BIOS — using Globally Unique Identifier (GUID) partitions will be required before >2.19 TB drives can be used routinely as boot drives. This will come soon enough. It explains why Seagate made the 3TB model available only as an external storage device, for now, and allowed WD to be the first to put a bare 3TB drive on the market. WD did go the extra step of providing an AHCI-compliant host bus adapter (HBA) card with the retail drive kits, to allow the 3 TB drive to be used as a boot drive in a few PCs or as a secondary drive where the onboard SATA controllers/drivers don’t provide access to all of the 3TB capacity.
The 3TB Green model had a major impact on our new Silent Server Build Guide, posted just around the time of WD’s announcement. Our HDD of choice was the 2TB WD Green, six of them, to be precise, for a 12TB server rig. Now you can get the same capacity with just four drives, with reduced power, heat and noise. The 750 GB/platter density makes for some interesting prospects, such as a 1.5 TB 2-platter drive or a 2.25 TB 3-platter drive — in theory, these should be a couple of decibels quieter than the already amazingly quiet 4-platter models.
These interesting prospects are the reason we have waited till now to post our review of of the 3TB Green: It took a little while for our hardworking rep at WD to get us samples of a new 2TB Green which utilizes three platters, albeit of slightly lower areal density (667 GB/disc) than the 3TB model. This is similar to the new Samsung Spinpoint F4 EcoGreen 2TB, and unlike the previous WD Green 4-platter 2TB models. The point is to tell you about the acoustics and performance of the new 3-platter 2TB drive and the 4-platter 3TB drive and compare them to an older 2 TB Green AV-optimized drive, all in one article. There is a 2.5 TB model available as well, but mechanically, it shares the same 4-platter structure of the 3 TB model, so its acoustics will differ only with sample variance.
 WD Green 3 TB on left, new 2 TB WD20EARS in center, older 2 TB WD20EVDS on right. |
| Specifications (from PDF spec sheets) WD Caviar Green 3TB & 2TB | |||
| Model Number | WD30EZRS | WD20EARS | WD20EVDS |
| Capacity | 3 TB | 2 TB | 2 TB |
| Cache | 64 MB | 64 MB | 32 MB |
| Interface | SATA 3 Gbps | SATA 3 Gbps | SATA 3 Gbps |
| Rotational speed* | 5400 RPM | 5400 RPM | 5400 RPM |
| Heads / Disks* | 8 / 4 | 6 / 3 | 8 / 4 |
| Avg ready time | n/a | n/a | 14.5 ms |
| Average latency | n/a | n/a | 4.2 ms |
| Transfer Rate | 110 MB/s | 110 MB/s | 110 MB/s |
| Weight* | 680 grams | 640 grams | 740 grams |
| Power: Read/Write Idle Standby Sleep | 6.25 W 5.50W 0.80 W 0.80 W | 4.50 W 2.50W 0.70 W 0.70 W | 5.90 W 4.90 W 0.70 W 0.70 W |
| Acoustics: Idle Seek Quiet Seek | 24 dBA 29 dBA 25 dBA | 24 dBA 29 dBA 25 dBA | 25 dBA n/a 26 dBA |
| * This information was assessed or derived independently through our testing and research, and is not found in WD specifications. | |||
There are several noteworthy points in the specs:
- It’s odd that "avg ready time" (the time from when the power is applied until the drive is ready to supply data), random access time and latency are not given for the new WD Caviar Green models.
- Not covered in the specs is the fact that the AV optimized WD20EVDS does not have the head park feature of the other drives.
- The newer 3 TB drive is 60 grams lighter than the older 2 TB drive, even though they both have 4 platters. Perhaps that weight is accounted for by the bigger controller PCB on the WD20EVDS; perhaps the difference is in the new platters as well.
- The absence of a standard seek acoustics spec for the WD20EVDS suggests AAM is locked in quiet mode.
- The new 3-platter WD20EARS has reduced power requirements.
3 TB WD CAVIAR GREEN DETAILS
The AHCI-compliant host bus adapter (HBA) card that came with our sample of the WD Green 3TB is a HighPoint Technologies RocketRAID 62X, which goes into a PCI Express slot. This card allows access to the drive’s full 3 TB capacity in most cases where the native SATA ports on the motherboard don’t.
 HighPoint RocketRAID 62X card with two SATA ports is provided with the 3 TB WD Caviar Green. |
It is not possible to boot from the WD Green 3TB even with Windows 7 64-bit unless your motherboard is equipped with an EFI that supports a GUID Partition Table (GPT). Windows 7-64 will identify the drive as a GPT type incompatible with the BIOS and prevent installation to it unless your motherboard supports it. This is exactly what happened with our Asus
P6X58D Premium motherboard. In another month or two when the boards for Sandy Bridge appear, they will certainly will allow booting from a >2.19 TB drive (if you run a 64-bit Windows).
The idea of using a 3 TB primary boot drive is a little silly, though. In this day and age, it is better practise to install the OS and programs on an SSD of adequate capacity (say 30~120 GB depending on your particular applications) and to use a high capacity drive for data storage.
The above mentioned Asus
P6X58D Premium motherboard, in a Windows 7 64-bit system, had no trouble recognizing via its own SATA ports, and using the 3 TB Caviar Green as an additional drive (D, E or what have you) . Full 3 TB recognition varied among the PCs in our lab. Most of the non-64-bit Windows in our lab saw only 2.19 TB in this drive unless it was connected through the HBA card supplied by WD.
TESTING
Our samples were tested according to our standard
hard drive testing methodology. As of mid-2008, we have been conducting
most acoustics tests in our
own 10~11 dBA anechoic chamber, which results in more accurate, lower SPL
readings than before, especially with <20 dBA@1m SPL. Our methodology focuses
specifically on noise, and great effort is taken to ensure it is comprehensively
measured and described. Performance is covered only lightly, for reasons discussed
in detail in the methodology article.
Two forms of hard drive noise are measured:
- Airborne acoustics
- Vibration-induced noise.
These two types of noise impact the subjective
perception of hard drive noise differently depending on how and where the drive
is mounted.
Both forms of noise are evaluated objectively and
subjectively. Airborne acoustics are measured in our anechoic chamber using a lab reference
microphone and computer audio measurement system. Measurements are taken at a distance of one meter from the top
of the drive using an A-weighted filter. Vibration noise is rated on a scale
of 1-10 by comparing against our standard reference drives.
Summary of primary HDD testing tools:
- Hitachi
Feature Tool – DOS utility used primarily to check/set Automatic Acoustic
Management and for its intense seek simulation utility - HDTach
– Low level hardware benchmark for random access read/write storage devices - IOMeter – I/O
subsystem measurement and characterization tool for single and clustered systems.
It is used as a benchmark and troubleshooting tool - HD Tune Pro 4.6
– Benchmarking tool for storage devices - SpeedFan
– Monitor system sensors such as HDD temperature - SPCR’s Audio Audio
Recording/Analysis system using SpectraPlus
and other utilities - SPCR Anechoic Chamber
- Custom-built HDD power
measurement and Vibration test tools
Test System:
- Intel Core i7-965 Extreme
Nehalem core, LGA1366, 3.2GHz, 45nm, 130W TDP. - Asus
P6X58D Premium ATX motherboard. X58 chipset. - Asus
EAH3450 Silent graphics card. - Intel
X25-M 80GB 2.5" solid-state drive. Chosen for silence. - 3GB QiMonda
DDR3 memory. 3 x 1GB DDR3-1066 in triple channel. - Seasonic X-650 SS-650KM
650W ATX power supply. This PSU is semi-passively cooled. At the power levels
of our test platform, its fan does not spin.
A final caveat: As with most reviews, our comments
are relevant to the samples we tested. Your sample may not be identical. There
are always some sample variances, and manufacturers also make changes without
telling everyone.
Ambient conditions at time of testing were 10.5 dBA and 22°C.
 Our 3TB Green sample was manufactured in Malaysia in Sept 2010. |
 The 2TB 3-platter Green sample came from Thailand a month earlier. The label’s voltage/current data does not make sense; they are higher than for the 3-TB drive. |
 This 2TB 4-platter Green sample was also made in Thailand, but a year ago. |
PERFORMANCE
The table below is a summary of read performance test data from testing with HD Tach 3.0.4 and HD Tune 4.6. All the drives were connected directly to the onboard SATA ports of the test platform system described on the previous page: A Windows 7 64-bit OS on a Asus
P6X58D Premium ATX motherboard with an Intel Core i7 Extreme 965 processor.
| Model | WD30EZRS | WD20EARS | WD20EVDS |
| HD Tune 4.6 Sequential Read Results | |||
| Min read | 60.9 MB/s | 51.5 MB/s | 47.1 MB/s |
| Max read | 130.5 MB/s | 132.1 MB/s | 107.3 MB/s |
| Avg read | 103.2 MB/s | 98.5 MB/s | 80.5 MB/s |
| Random access | 20.4 ms | 19.9 ms | 20.4 ms |
| HD Tach Sequential Read Results | |||
| Sequential read | 120.7 MB/s | 103.0 MB/s | 84.1 MB/s |
| Random access | 13.9 | 15.0 ms | 20.0 ms |
The two higher areal density drives were expected to run a bit faster. This was the result in HD Tune, but HD Tach showed the 3 TB model to be faster than the new 2 TB. The difference was about the same margin as the 3-platter WD20EARS over the WD20EVDS. However, even though HD Tach shows the big drive as being 3 TB, this software does not have explicit support for a 3 TB drive, while HD Tune does. It is possible that HD Tach short strokes the drive (ie, uses only 2.19 TB of total capacity) in testing, which could explain the higher reported speed.
HD Tune was also used test test write operations,. Sequential Write as well as Random Writes. HD Tune calls for an unpartitioned drifve and writes across the full area of the drive. The sequential write results more or less mirrored the read results. The only unlikely result was Random Access of ~7 ms for the 2 TB AV drive, despite the same result being obtained many times.
| HD Tune Sequential Write Results | |||
| Model | WD30EZRS | WD20EARS | WD20EVDS |
| Avg write | 99.3 MB/s | 96.0 MB/s | 79.7 MB/s |
| Max write | 125.4 MB/s | 127.3 MB/s | 103.5 MB/s |
| Min write | 57.9 MB/s | 50.0 MB/s | 46.6 MB/s |
| Random access | 19.2 ms | 19.2 ms | 7.11s |
RANDOM ACCESS READ/WRITE
Random Write / Read tests were done with files sizes from 512 bytes to 1 MB. HD Tune Pro 4.6 provides IOPS measurements as well as access time and speed.
| HD Tach Random Access Reads    |
There wasn’t much to choose among the three for random access reads. But in Random Access Write operations, the 2TB AV version came out on top, in some cases by a significant margin.
| HD Tach Random Access Writes    |
TIMED FILE TRANSFERS
In real world file transfer timed tests from/to an OCZ Vertex 2 60GB SSD:
1) Small File Copy: A 870 MB folder of 1,278 files ranging from 10KB to 4MB in size
2) Large File Copy: 4 GB folder of 4 files, 2 x 700MB and 2 x 1400MB in size
The three drives both wrote and read within a few percent of each other. In actual use, you would be hard pressed to notice any difference. Only with a huge single 40 GB file ripped from a Bluray disc was there any significant difference, and oddly, the 3-platter WD20EARS came out on top.
| Timed Results (read/write in seconds) | |||
| Model | WD30EZRS | WD20EARS | WD20EVDS |
| Small files | 13 / 18 sec | 13 / 18 sec | 13 / 16 sec |
| Large files | 43 / 41 sec | 42 / 46 sec | 42 / 45 sec |
| 40 GB file | 355 / 332 sec | 307 / 306 sec | 394 / 405 sec |
ACOUSTICS, VIBRATION & POWER
3 TB Model: WD Greens have been quiet leaders among hard drives for some time. Our sample of the new 3 TB Green was very quiet, but it did not set records. It was about a decibel louder than previous 4-platter WD Green models, and vibrated a bit more, ranked at level 8 of our vibration test. Whether this is sample vairance or typical of the model is not possible to say without many more samples. We do have six samples of the WD20EVDS, an AV version of the 2 TB 4-platter model, and they are split evenly between level 8 and level 9 vibration , so it’s not unreasonable to conjecture that some of the new 3 TB samples will also exhibit even less vibration.
Seek noise was extremely muted, with peaks just barely over the idle SPL. HD Tune 4.6 showed Automatic Acoustic Management (AAM) to be set at default to minimum noise (128 vs 256), like all the recent WD Greens we’ve encountered, including the other two samples closely examined here.
The 3 TB sample drew one watt higher peaks in seek than previous 4-platter samples, but its idle power was similarly low at around 4W. The 90 Hz fundamental peak confirms that it runs at same 5400 RPM speed as all the WD Greens we have tested over the years.
| WD GREEN 3 & 2 TB MODEL COMPARISON | ||||
| HDD Mfg date firmware version | Vibration 1-10 (10 = no vibration) | Activity State | Airborne Acoustics (dBA@1m) | Measured Power |
| WD Caviar Green 3TB WD30EZRS 18 Sept 2010 firmware 01.00A01 (750 GB/disc) | 8 | Idle | 14.6 | 4.1 W (3.7 W heads parked) |
| Seek | 14~15 | 7.5 W | ||
| WD Caviar Green 2TB WD20EARS 3 Aug 2010 firmware 01.00A01 (667 GB/disc) | 9 | Idle | 12.8 | 2.8 W (2.4 W heads parked) |
| Seek | 12~13 | 6.5 W | ||
| WD Caviar Green 2TB WD20EVDS Nov 2009 firmware 01.00A01 (500 GB/disc) | 8~9 | Idle | 13.6 | 3.9 W (no head park) |
| Seek | 13~14 | 6.5 W | ||
2 TB (3-platter) Model: This sample was the record-setter. It is our quietest WD Green sample by a hair, just about the quietest hard drive we’ve tested when both idle and seek noise are considered, its vibration level is extremely low, and its idle power of 2.4W almost approaches notebook drive lows. The surprise is that this sample was made in August 2010, which suggests that it may have been selling in the marketplace for many months. There may be many lucky consumers who simply bought a "2 TB WD Green", and instead of receiving one of the older 4-platter variants, got this slightly quieter newer version 3-platter drive instead.
2 TB (4-platter) AV Model: The AV variant should be identical to the standard 2 TB 4-platter WD Green, as the only difference is the absence of the head park feature standard to WD green drives. Head park kicks in when the drive is idle for more than a few seconds. It is intended mostly to reduce energy consumption. For audio-video (including surveillance) applications where the drives are active 24/7, it could become a point of failure from over use, so the feature is left off. As mentioned, we have six samples, and the SPL variance among them is less than 1 dBA@1m; we picked one of the quieter ones. The vibration, as mentioned, varied a bit from sample to sample. The power consumption was very consistent, within a couple percent. Peak power of 6.5W is very modest, and the idle of ~4W is excellent and about par for WD Green 4-platter models.
 The rotation of the platters causes a low frequency spike between 80 and 100 Hz, suggesting that the EcoGreen F4 spins at close to 5400 RPM. |
HIGH CAPACITY DRIVE COMPARISON TABLE
| HIGH CAPACITY 5,400 ~ 5,900 RPM DESKTOP DRIVES | ||||
| HDD Mfg date firmware version | Vibration 1-10 (10 = no vibration) | Activity State | Airborne Acoustics (dBA@1m) | Measured Power |
| WD Caviar Green 3TB WD30EZRS 18 Sept 2010 firmware 01.00A01 | 8 | Idle | 14.6 | 4.1 W (3.7 W heads parked) |
| Seek | 14~15 | 7.5 W | ||
| WD Caviar Green 2TB WD20EARS 3 Aug 2010 firmware 01.00A01 | 9 | Idle | 12.8 | 2.8 W (2.4 W heads parked) |
| Seek | 12~13 | 6.5 W | ||
| WD Caviar Green 2TB WD20EVDS Nov 2009 firmware 01.00A01 | 8~9 | Idle | 13.6 | 3.9 W (no head park) |
| Seek | 13~14 | 6.5 W | ||
| WD Caviar Green 2TB WD20EADS February 2009 firmware 01.00A01 | 7 | Idle | 13.9 | 4.5 W (2.8 W heads parked) |
| Seek | 13~14 | 5.8 W | ||
| WD Caviar Green 1.5TB WD15EADS November 2009 firmware 01.00A01 | 9 | Idle | 12.9 | 4.5 W (2.8 W heads parked) |
| Seek | 13~14 | 5.8 W | ||
| Samsung EcoGreen F4 2TB HD204UI August 2010 firmware 1AQ10001 | 7 | Idle | 13 | 4.0 W |
| Seek | 15 | 5.6 W | ||
| Seagate Barracuda LP 2TB ST32000542AS June 2009 firmware CC32 | 6 | Idle | 14 | 4.7W |
| Seek | 17 | 7.9W | ||
| Samsung EcoGreen F3 2TB HD203WI May 2010 firmware 1AN10003 | 7 | Idle | 15~16 | 4.7 W |
| AAM | 17~18 | 6.1 W | ||
| Seek | 18~19 | 6.9 W | ||
| Seagate Barracuda LP 2TB ST32000542AS June 2009 firmware CC32 | 6 | Idle | 15 | 4.4 W |
| Seek | `7 | 8.6 W | ||
As the table lays out plainly, the new 3-platter 2 TB WD Green is at least as quiet as the equivalent Samsung EcoGreen F4 in idle, and quieter in seek. It has much lower vibration and power consumption is also lower. From the acoustic / power efficiency standpoint, the WD20EARS has no peer. The closest competition is from an earlier WD Green, the 3-platter 1.5 TB model.
CONCLUSIONS
The new 750 and 667 GB/platter density Caviar Greens extend WD’s lead in hard drive energy efficiency and low noise. The ability for a DIY builder to assemble a massive 12 TB server with just four drives or even have 6 TB of storage in just two extra drives in the PC under the desk is a staggering thought. Our 3 TB model was a touch noisier than most of our other 4-platter WD Green samples, but this is likely the result of normal sample variance. WD’s approach of including an AHCI-compliant host bus adapter (HBA) card with the new >2 TB drives is a bold one, but it adds to the cost of the product, which surely must impact sales. WD — and the other drive makers with similarly high capacity drives awaiting — is surely looking forward to the soon-to-come transition to UEFI in place of the BIOS and its legacy-imposed 2.19 TB limitation.
We like the 3TB Green, but we love the new 2TB Green. The new 3-platter 2TB WD Green, model WD20EARS, is a sweet spot product at this tine. 2TB Greens are routinely selling for $100 or less these days, which is a bargain when you consider the performance and the fact that our two samples are the quietest hard drives we’ve tested, with extremely low vibration. It’s better in this regard than just about any laptop drives of any size or speed, and its idle power is almost as low, dropping to just 2.4W when the heads are parked.
The storage scheme for a quiet desktop PC of a modest size (80~120 GB) high performance SSD for the OS and programs, plus a high density WD Caviar Green for data is more compelling than ever.
Many thanks to WD for the
review samples.
WD Caviar Green 2TB WD20EARS
SPCR Editor’s Choice Award
* * *
SPCR Articles of Related Interest
Samsung EcoGreen F4 & Seagate Barracuda XT 2TB Hard Drives
Consumer SSD Battle: WD, Kingston, OCZ, Intel
WD Caviar Black 2TB & VelociRaptor 600GB
Western
Digital Green 1.5TB vs. Seagate 7200.12 500GB
5900rpm
Seagate Hard Drives: Barracuda LP, Pipeline HD .2
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