Article Thumbnail

Western Digital Green vs. Red Hard Drives

Written on October 7, 2014 by Matt Bach
Share:
Table of Contents:
  1. Introduction
  2. Basic Specifications
  3. Features
  4. Performance
  5. Reliability/Data Integrity
  6. Power Management
  7. Environmental Specifications (noise)
  8. Physical Dimensions
  9. Conclusion

Introduction

Here at Puget Systems, we sell a lot of hard drives, with a good chunk being WD (Western Digital) Green drives. Especially in our Serenity systems, the quiet operation of the Green drives is essential when a customer wants a lot of storage space without the added noise that usually accompanies hard drives. However, we have recently decided to retire the WD Green drives from many of our systems, moving instead to the NAS and RAID oriented Red drives that are also made by WD. In working with the drives and examining the specifications closely, we have found that there is actually very little downside to Red drives compared to Green drives, but a number or advantages.

WD Green vs Red

For our customers that want quiet systems, moving away from the tried and true Green drives may seem like an odd decision, so in this article we are going to compare the Green and Red lines and show why we believe that this is a good move. One thing we want to note is that all of this information is only valid for the latest revision of these drives. If you go back even one or two revisions, the differences between the two lines are completely different.

Because there are so many specifications and features to go over, we will be dividing this article into separate sections based on the categories that WD uses in their spec sheets. These categories include basic specifications, features, performance, reliability/data integrity, power management, environmental specifications (including noise levels), and physical dimensions. If you rather just see a summary of why we are making this move, feel free to jump ahead to the Conclusion section. Likewise, if you would rather just see all the specifications at a glance without any of our commentary, simply expand the option below:

[+] Show WD Green vs. Red Specification Comparison

Basic Specifications

Basic Specifications Green 1/2/3/4/5/6 TB
(EZRX Series)
Red 1/2/3/4/5/6 TB
(EFRX Series)
Interface SATA 6Gb/s SATA 6Gb/s
Formatted capacity 1/2/3/4/5/6 TB 1/2/3/4/5/6 TB
Native command queuing Yes Yes
Form factor 3.5-inch 3.5-inch
Advanceed Format (AF) Yes Yes
RoHS compliant Yes Yes
Newegg Price $65/85/110/150/223/270 $70/100/122/170/235/290

From a very basic standpoint, the two model lines are essentially the same. They are both 3.5-inch SATA 6GB/s drives that include 1, 2, 3, 4 and 6 TB versions. The main difference we want to point out here is the price. If you were to purchase a drive as a stand alone part from Newegg, a Red drive would be cost about $5 more per terabyte than a Green drive. This isn't much, but depending on the model you may have to spend up to $20 more for a Red drive than a Green drive.

Features

Features Green 1/2/3/4/5/6 TB
(EZRX Series)
Red 1/2/3/4/5/6 TB
(EFRX Series)
TLER Support No Yes (7 seconds)
Vibration Protection None 3D Active Balance Plus
SED Support No No

From a features standpoint, the only major difference between Green and Red drives is TLER support. Neither drive supports SED, and 3D Active Balance Plus is really just WD's way of saying that the motor and platters are all balanced within a certain tolerance to ensure that vibration is kept to a minimum. In fact, it would probably be more accurate to classify 3D Active Balance Plus as a form of vibration dampening instead of vibration protection.

TLER (Time Limited Error Recovery) is a very important feature if you will be using the drive(s) in RAID since it limits the amount of time a hard drive can spend trying to recover from an error. Normally, if a data error is detected the hard drive will attempt to recover the data and repair the error. Depending on the nature and severity of the error, this can take anywhere from a few milliseconds to a couple of minutes. Normally, this isn't a big deal - it just results in the data not being available for a bit longer than normal. However, RAID controllers only allow for a short amount of recovery time (usually about 7-14 seconds) before the controller assumes that the drive is having problems, drops the drive from the array, and marks the array as degraded.

What TLER does is limit the amount of time the hard drive can spend trying to repair an error before giving up. Since many types of RAID have built-in error correcting, it is preferable to let the RAID itself repair the error than to let the hard drive drop and degrade the RAID array. While TLER is absolutely great if the drive is used in a RAID array, it is not useful (and could even be a negative) if the drive is simply a stand-alone drive. Luckily, WD has provided us with proprietary tools that allow us disable TLER on systems that do not have RAID arrays. 

Performance

Performance Green 1/2/3/4/5/6 TB
(EZRX Series)
Red 1/2/3/4/5/6 TB
(EFRX Series)
Buffer to host 6 Gb/s 6 Gb/s
Transfer Rate to/from drive
(sustained)
150/147/147/150/170/175 MB/s 150/147/147/150/170/175 MB/s
Cache (MB) 64 64
Rotational speed (RPM) IntelliPower IntelliPower

For drive performance, the Green and Red drives are actually completely identical according to the WD specifications. Unlike RE drives - which we have found to be faster than Black drives even though they are also rated to have the same performance - our testing has shown that Green and Red drives do indeed perform exactly the same.

Reliability/Data Integrity

Reliability/Data Integrity Green 1/2/3/4/5/6 TB
(EZRX Series)
Red 1/2/3/4/5/6 TB
(EFRX Series)
Load/unload cycles 300,000 600,000
Non-recoverable read errors per bits read <1 in 10^14 <1 in 10^14
MTBF (hours) Unlisted 1,000,000
Limited Warranty 2 year 3 year

Since Red drives are designed to be used in RAID arrays and NAS units, it is no surprise that they are rated for double the load/unload cycles as Green drives. A load/unload cycle is when the disk spins up its platter to get ready for operation. Typically this happens when you turn on a system, resume from standby, or when the drive has been idle long enough for the OS to power down the drive. While Red drives are rated for twice the number of load/unload cycles, the 300,000 cycles the Green drives are rated for is really quite a lot already. Even if you turn on/off your system or let it idle long enough to power down the drive 20 times a day, 365 days a year, a Green drive should still last for over 40 years.

In addition to the greater load/unload cycles, Red drives also carry a 3 year warranty from WD compared to the shorter 2 year warranty found on Green drives.

Power Management

Power Management Green 1/2/3/4/5/6 TB
(EZRX Series)
Red 1/2/3/4/5/6 TB
(EFRX Series)
12VDC +- 10% (A, peak) 1.2/1.73/1.73/1.75/1.75/1.75 A 1.2/1.73/1.73/1.75/1.75/1.75 A
Read/Write 3.3/4.1/4.1/5.3/5.3/5.3 W 3.3/4.1/4.1/4.5/5.3/5.3 W
Idle 2.5/3.0/3.0/3.4/3.4/3.4 W 2.3/2.7/2.7/3.3/3.4/3.4 W
Standby/Sleep .4W .4W
Head parking delay 8 seconds 300 seconds (5 minutes)

Comparing the power management specifications between these two drive lines is actually fairly interesting. Green drives are specifically designed for lower power operation, yet the Red drives either have the same or lower power draw depending on the model. In fact, really the only place where Green drives are more "green" is due to a firmware tweak which makes the drive head park after only 8 seconds instead of the normal 300 seconds found on most other WD drives (including Reds).

When a hard drive is under normal operation, the data heads (which both read and write data to/from the platters) float just a few nanometers above the platter. The heads are so close to the platter - which is spinning at thousands of RPM - that they introduce a certain amount of drag which the motor has to work harder to overcome. Head parking is simply the act of moving the heads away from the platters so that they no longer cause any drag. While this does result in the motor drawing a little less power, there are a few downsides to head parking.

The first issue with head parking is that the "landing zone" (where the heads rest while parked) is something that can physically wear out over time. The landing zone is usually rated for hundreds of thousands of uses, but every time the heads park you are one tiny step closer to the drive failing. In addition, it takes a tiny amount of time for the heads to return to a working position after they have been parked so there is a tiny (virtually imperceptible) drop in performance while the heads are unparked for use.

To determine the power savings of head parking, we used a multimeter to measure the wattage of both a 6TB Green and 6TB Red drive at load, normal idle and idle after the head was parked:

From our measurements, having the head parked resulted in a power draw reduction of about .7 watts. This is really a tiny difference, but if you are incredibly power conscious it may be relevant. Just keep in mind that the shorter the hard parking delay, the more wear the drive will sustain which may result in a shorter drive lifecycle.

One thing we want to point out is that WD does have a utility called WDIDLE3 that can change the parking delay on Green and Red drives. It is only available for download through one of their legacy drives (so no guarantee that it will work for all models) but we have successfully used it to change the parking delay on a number of Green and Red drives. So if you have a Green drive but want to make the delay longer (or want to shorten the delay on a Red drive) you currently are able to do so.

Environmental Specifications (noise)

Environmental Specifications Green 1/2/3/4/5/6 TB
(EZRX Series)
Red 1/2/3/4/5/6 TB
(EFRX Series)
Temperature - operating (°C) 0 to 60 0 to 65
Temperature - non-operating (°C) -40 to 70 -40 to 70
Shock - operating - 2 ms, write (Gs) 30 30
Shock - operating - 2 ms, read (Gs) 65 65
Shock - non-operating (Gs) 250 250
Acoustics - Idle 21/23/23/25/25/25 dBA 21/23/23/25/25/25 dBA
Acoustics - Seek (average) 24/27/27/28/28/28 dBA 22/24/24/28/28/28 dBA

While Red drives are rated to operate at slightly higher temperatures, the interesting specification here is the seek acoustics. Even though we have used Green drives in our quietest systems for years, it turns out that the latest models of Red drives are rated to be just as quiet or quieter than their Green counterparts. From our understanding, there is no reason that Red drives should be any quieter, so there is the possibility that this is simply a testing artifact due to the extremely quiet nature of these drives. When you are testing components at 25 dBA, even something as small as a truck driving past on a road a couple blocks away can raise the decibel readings a couple of points.

Either way, Red drives are at least as quiet or quieter than Green drives which is great to know.

Physical Dimensions

Physical Dimensions Green 1/2/3/4/5/6 TB
(EZRX Series)
Red 1/2/3/4/5/6 TB
(EFRX Series)
Size - L/W/H (in.) 5.787/4/1.028 5.787/4/1.028
Weight .99/1.32/1.4/1.5/1.65/1.65 lb .99/1.32/1.4/1.5/1.65/1.65 lb

Finally, for an anti-climatic end, the Green and Red drives are the same physical size and weight for each storage capacity.

Conclusion

Overall, the differences between WD Green and Red drives are very subtle. From a noise, power draw, and performance standpoint Green and Red drives are pretty much identical. Really the only major specification difference between the two drive lines is that Red drives support TLER (critical for RAID arrays), have a longer expected lifespan, and an extra year of warranty. Red drives also have a longer head parking delay than Green drives, which can either be a pro or a con depending on if you want to reduce power draw as much as possible or maximize performance and lifespan.

The only real downside to purchasing a Red drive instead of a Green drive is the price. The difference is only about $5 per terabyte, however, which in our opinion is well worth the longer lifespan and additional year of warranty alone. 

In the coming weeks, look for more and more of our certified systems to move from Green drives to Red drives. This is a pretty big move, and we would absolutely love to hear what you think about it. Let us know in the comments below!

Tags: Western Digital, WD, Green, Red
Gravitysmith

Great timing!

Just this morning I was window shopping your site, researching what components I will want for my next machine. Power consumption and performance are my top priorities. I don't yet know all the differences between green, blue, red, black drives, but I do know I can watch the peak power usage number near the price in your configurator.

Anyhow, when I got to the hard-drives, I saw the red and green were essentially identical. I made a mental note to research the differences later, but now you have brought the answers to me. Thank you! The article couldn't have been presented any better and shows me the red is what I want.

Only one speculation remains ... if green is supposed to be the most power efficient, will Western Digital soon refresh that line of drives for even lower power consumption?

Posted on 2014-10-08 00:59:40
June

I wonder if the WD proprietary tool is something other than WDTLER.EXE. As per http://en.wikipedia.org/wiki/E... that tool WD removed it due to the risk of firmware damage on new drives. The alternative tool 'smartctl' doesn't seem straightforward to use and I read it requires to be launched on each boot up.

Posted on 2014-10-10 15:15:16
Ankur Sethi

Great article thank you, I particularly noted the TLER and vibration support.

Posted on 2015-02-06 17:09:52
Phil Goetz

WD used to provide a utility to change the head park time. But it works only on 32-bit Windows. Can we change the park time on Greens some other way?

Posted on 2015-03-31 04:16:24
Hitagi

Great article! Any links to the mentioned WD disable TLER tool? As WD removed the wdtler tool in their site.

Posted on 2015-07-11 08:14:21
Tu Pham

Ive been using NAS Storage for around 7 years now and have been happy using the WD Caviar Greens since the 1TB WDEAC10s were around. Ive gone from 4 x 1TBs to the 4 x 2TBs and now I have 4 x 3TBs. I only had not one failure throughout the years, with the eception of one DOA back when the Greens were new and got it swapped over right away. So anyway, given that I intend to use the 3TBs well beyod the warranty period, I don't really see the point in paying the extra dollars. at the combined cost of 4 x 3TB Hard drives, you'd almost be paying for an additional drive. So Id rather pocket the cash and if a drive were to fail after warranty is over, then the money you pocketed can probably be used to buy a 10TB drive!

Posted on 2015-09-12 06:10:32
Kidou

Hi All

I have a ZyXEL NSA325 v2 2 Bay Desktop Network Storage 2x 3tb Green WD30EZRX drives in a jbod arrangement. Do I have to alter the parking head delay or is that just if you have a raid setup? Thanks.

Posted on 2015-10-28 10:27:39
Joel Bensonetti

Haven't needed a new HDD for a couple of years but now that I do, I found this particularly useful. It seems that WD has discontinued their green series (they must have read your article;) and I'm seeing them on sale in a few places being touted as the greatest thing that was retired... Well now I know why. I prefer to have a drive parking every 5 minutes instead of 8 seconds, what were they even thinking? Oh yeah, money. Anyway, thanks again. Bet a lot more people come here to read this in the future!

Posted on 2016-07-03 13:13:49

Yes definitely get something else. Idk what your intended use is, but I have 5 3tb reds running in a file server with btrfs raid 10 and am very satisfied, both by the drives and the file system (some will disagree but btrfs has been completely stable for me and hasn't lost me any data). I run scrubs and smartctl long tests weekly and there is no sign of errors. The array is also very fast, large file reads/writes are basically number of drives * speed per drive so between 500 and 800 MB/s. Many small operations are of course slower but that's what ssds are for. I wouldn't recommend raid5 or 6 yet. Raid 5 looks attractive but with that many drives the chances of another drive failing during a rebuild are a bit high for me. Raid6 fixes this but btrfs implementation is not as good as zfs raid z2 (basically the equivalent of raid 6 only with stripe size being adaptable unlike with ride 6 which has a fixed stripe size which is really bad for performance, since unless you are writing things that are exact multiples of the stripe size, you need to read the existing stripes update the changed data and write it back which is slow.... the second set of parity calculations is also a bit harder than the first one but that's not really an issue on any modern cpu). Snapshots, subvolumes (both of these are great for many things, for example backups and with a copy on write filesystem both are very cheap operations space and cpu wise), on the fly compression (not sure about which algorithms zfs uses but btrfs uses lzo and zlib, lzo is less efficient but faster and zlib is more efficient but slower.... I'd recommend using lzo on all drives since the cpu performance required is negligible but the io performance can improve nicely if you are working with compressible files (it's smart about what to compress and what not to so it wont try to compress things that are already compressed)), scrubbing (basically btrfs and zfs both store a checksum for each block written and can detect and repair file corruption caused by bitrot), copy on write (basically means that any block is only copied once changes are made to it) and data deduplication (btrfs has offline data deduplication while zfs has online... both have their advantages and disadvantages) are all cool features to have.

tl;dr

reds are nice drives for their price and btrfs/zfs are very nice filesystems it's a shame they aren't available on Windows/OsX

Posted on 2016-07-12 19:37:44