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Antec MX-1: Actively Cooled External HDD Enclosure

March 29, 2007 by Mike Chin

Product
Antec MX-1

Actively Cooled HDD Enclosure
Manufacturer
Antec
Suggested Price
US$70

 

UPDATE - June 29, 2008

Occasional comments about the fan in the MX-1 being noisier than described here surfaced in the discussion thread very soon after this article was posted. They were a minority, however, as many reported the similar quiet acoustics we found. Over time, however, the complaints about the MX-1's fan noise have grown. We caution prospective buyers that the production fan might have changed (without any official version change), in which case, our acoustic assessment might no longer be valid.

External single hard drive enclosures are a dime a dozen. Almost every brand in the PC industry has at least one, and often, many more than one. They appear to vary only by appearance, interface options, and price. The most common interface is USB 2.0, but eSATA (external SATA) is becoming increasingly popular, and Firewire or IEEE 1394 appears to be on the wane. The typical HDD enclosure is made of extruded aluminum pieces that fit into each other. Usually it's only marginally bigger than the drive it encloses. Some are made of plastic or a combination of plastic and aluminum. On one end, there is an input/output panel, and perhaps a power switch. They are invariably powered by an external power dongle that supplies the 12V and 5V lines need by 3.5" drives.

There is rarely any attention paid to cooling other than the conduction between the HDD and the aluminum. In the plastic boxes, the conduction is pretty ineffective for cooling. In most cases, the drive tends to get pretty hot after a short while. The few that have active cooling usually use a tiny 40mm fan more notable for its whiny noise than for effective cooling. For most SPCR readers, fan cooled external HDD boxes are anathema. Noise conscious users try to combine a quiet drive like one from SPCR's recommended list with an enclosure that's reasonably sturdy, fanless, and not too resonant.



It looks a bit different from most HDD enclosures.

Its singular Antec logo and soft blue LED aren't loud, either.

The MX-1 is Antec's first and only external hard drive enclosure, and it's decidedly different from any others we've seen. They pointedly call it an Actively Cooled Hard Drive Enclosure. It include a fan, one quiet enough that Antec says it measures less than 22 [email protected] That's quieter than most hard drives. It's made mostly of plastic, but Antec also claims it keeps the drive very cool. Those are pretty good reasons for us to be interested:

  • It is possible to boot from an eSATA drive, which means the main PC can be completely free of any HDD noise, and the OS drive could be remotely located in an acoustically isolated position. The speed of eSATA is essentially identical to SATA, which makes this a no-compromise from a performance perspective.
  • Single high capacity hard drives (500~1000GB) are handy for storing large numbers of big video, music, and photo files, but they tend to be multiple platter, with higher than usual noise and vibration. Remotely locating such a data drive has always been one of SPCR's recommended strategies for low noise operation. The MX-1 shows promise in this role.
  • Even a bare hard drive running while resting on a table top in cool 20°C room quickly reaches ~50°C. (A drive's temperature inside a well designed quiet PC will be a good 10°C lower, because the HDD will be positioned in the main airflow path of the case.) The upper safe operational limit for modern HDDs is 55~60°C. Any external enclosure that provides good cooling with no additional audible noise is welcome.

SPECIFICATIONS (from Antec's MX-1 product page)

  • Dual output interface - USB2.0 and eSATA (external
    Serial ATA) allows you to transfer data up to
    480Mbps or 3Gbps respectively
  • Support up to 750G SATA hard disk drive
  • Unique HDD cooler brings fresh air in and around the
    HDD for maximum cooling to protect your valuable asset
  • Two layer (plastic with aluminum) structure upper
    and lower covers to absorb HDD and fan noise
  • Carbon-glass filled frame to reinforce the strength of
    the whole enclosure
  • Built-in silicone pad to absorb HDD noise
  • Included USB cable, eSATA cable, and eSATA bracket
    to convert internal SATA to eSATA
  • Stand included
  • Very quiet fan operation - under 22 dBA (presumably at one meter)
  • Noise Level: 20 dbA with the blower on inside the
    enclosure
  • Supports Windows 2000 / XP / ME / VISTA

Additional Data:

  • Dimensions: 2.25" x 5.75" x 8.7" (5.7 x 14.6 x 22 cm)
  • Input: 100~240 VAC, 47/64 Hz, 1A
  • Output: 5V, 1.5A; 12V 1.8A

Aside from the slight discrepancy in dBA numbers (22 vs. 20), there's nothing askance here.

PACKAGING

The MX-1 comes in a typical full-color corrugated retail box with a plastic handle. (We don't know what the VERIS mark is about.)



A typical retail package box: At least no throwaway plastic is used!

Inside, the contents are more plentiful than you'd expect for a drive enclosure. Clockwise from the left in the photo below, there's the MX-1 itself, which is a bit bigger than most, a ~1m eSATA cable, a SATA-to-eSATA adapter plate (for PCI slot cover), a plastic vertical stand, a ~1m USB cable, two fold letter sheets of instructions, four long screws for HDD mounting, and a small AC/DC adapter.



Lots of goodies in the box.

Here is the business end of the MX-1. This end has it all: eSATA and USB connectors, power connector, power switch, intake vent above and exhaust vent below.



The business end of the MX-1

There are four small hard rubber pads on the bottom. Both the top and bottom panels have an outer skin of aluminum over a plastic base, much like the side panels of the Antec P180, presumably for improved stiffness and acoustic insulation. It's not heavy, but feels sturdy and well built.

INSTALLATION

Access to the interior is gained by the removable of a single long screw from the bottom. The top cover must then be slid a bit to be unlocked, after which it can be removed. What greets the eyes is a PCB with the I/O panel, a central blower style fan, and a one-piece silicone rubber grommet against which the hard drive is to be mounted.



More complex inside than most.

Two screws on either side of the fan allow the internal subassembly to be removed so that the HDD can be attached with screws threaded from the other side. A bit of care must be exercise when removing and reattaching the internal subassembly, as there is a bit of interlocking of plastic parts and a wire to blue LED power light under the Antec logo on the front of the device.



Subassembly holds the HDD and everything else.

We took a quick look at the underside of the PCB. A SATALink IC is employed.

The fan itself has a diameter of 70~80mm, with a fairly large center pole. The blades are quite short and have a depth no greater than 1cm at most, probably less. The intake is the circular opening you see above. It does not look like it moves much air... but to cool a single hard drive, it does not have to. The next photo shows the underside of the internal subassembly.



Long HDD screws "borrowed" from Antec P180, P150 and NSK2400/Fusion cases.

Proper grommets ensure no direct contact between HDD and subassembly.

INGENIOUS AIRFLOW

The arrows in the photo above give some idea of the way air flows within the MX-1. The left arrow shows a small gap between the fan and the bottom of the hard drive through which the fan draw in air. The rubber gasket between the subassembly and the bottom of the drive (visible under the left arrow) ensures that this is the only way the air can come into the fan. The arrow on the right shows the exhaust path, which is via the bottom slot.

You ask where the air comes from on the left. Well, there's only one way it can get into the MX-1, and that's through the intake vent on the top cover, directly over the exhaust slot. This means the air goes across the entire top surface of the drive, then around and under the drive, through the fan blades, then out the back. In essence, the air flows in a 180-degree loop over, around, and under the hard drive. The hard drive is literally surrounded by a soft flow of cooling air. The illustration below should explain this clearly.



The HDD is bathed in a cooling flow of air.

This design is ingenious in that it maximizes the surface area over which the air flows. Its effect should be similar to increasing the area of the cooling fins in a heatsink. A very modest flow of air will have a substantial cooling effect on the drive.

TESTING METHODOLOGY

The MX-1 was tested mostly for noise and cooling,
using a Western Digital Caviar SE16 500GB drive sample tested last summer. The drive was measured in free
air, and then again inside the enclosure to see how the enclosure affected
noise, cooling or power. Hence, noise, temperature and power measurements depend on the
drive installed
. Test techniques from our Standard HDD Testing Methodology were used.



HDD mounted, ready to be closed up. Note: The base is flipped 180 degrees in this photo.

For testing, the eSATA option was chosen. This required removing the back plate on a spare PCI slot in the computer(s), and installing the SATA-to-eSATA adapter plate. The adapter has a captive SATA cable that connects to any spare SATA port on the motherboard. It then provides an eSATA port on the back of the computer. As noted in our review of the Icy Dock external HDD enclosure, the eSATA connectors engage much more securely than standard SATA.

The following tools were used during testing:

  • B&K model 1613 sound level meter
  • Seasonic Power Angel AC power meter
  • PC system 1: P4-2.66 system with fully passive cooling and a damped 2.5" notebook running Windows XP — silent
    for practical purposes
  • PC system 2: AMD A64-X2 4800+ system with two suspended 3.5" HDDs, measuring ~23 [email protected] in a carpeted room
  • Hitachi
    HDD Feature Tool
    v2.04 — used to set AAM, check temperature
  • SpeedFan v4.28 to monitor temperature in Windows

Ambient conditions at the time of testing were 20 dBA and 21°C.

ACOUSTICS & VIBRATION

The MX-1 by itself

The first thing was to power up the MX-1 and have a listen to the fan. It was quiet, as promised. It measured around 20-21 [email protected], and sounded like a little hum from up close. There was little low or high frequency noise, and only a small amount of broadband wind noise. With the box closed, the noise softened and became essentially inaudible from a meter away. The airflow might be 10 cfm; it's not much, but enough to be easily felt at the vents.

In Idle Mode

The HDD sample is a quiet drive that originally measured 21 [email protected] (placed on a soft piece of foam). A recheck of the SPL gave a slightly higher reading: 22 [email protected] Whether this is due to changes in ambient noise conditions, or wear and tear on the drive itself is difficult to say.

Subjectively, the drive is much noisier than the fan of the MX-1. The HDD has a much greater low frequency noise, which is de-emphasized by the A-weighting applied to our dB measurements. That noise has its fundamental frequency at 120Hz, low enough to cause vibration-induced noise in most any object that comes in contact with the drive. (A 7200 rpm drive spins 120 times per second; ie, 120Hz.)

With the WD was installed in the MX-1 and powered up, the noise of the drive completely masked the noise of the internal fan. Placed atop a sturdy desk, there was a bit of vibration-borne hum, which was expected. The silicone gasket definitely helps, but it cannot eliminate all the vibration from getting conducted into the structure of the MX-1, and through it, into the desk. The power and data connections also provide a hard path for the HDD vibrations to be conducted through the PCB into the MX-1. Some of the increase in noise comes from cavitation effects: The drive "excites" the air resonances of the cavity (the interior space of the MX-1) and causes the noise to be a bit accentuated. This is simply unavoidable.

The noise of the drive in the MX-1 directly atop the desk measured 23 [email protected] Most of the increase was due to the mechanical vibration coupling and resonance effects. The hum reduced considerably when the unit was lifted and held off the desk, but the measured SPL did not change. Mounted vertically, the drive in the MX-1 displayed slightly less vibration than just by itself.

The overall contribution of the MX-1 to the noise of the hard drive was very small. Without paying close attention, the difference in noise between the bare drive and the MX-1 enclosed drive would be difficult for many people to notice.

In Seek Mode

The MX-1 with the WD drive was hooked up to the computer on the fly, while both were running. Device Manager in Windows XP Pro was used to recognize the external drive without any issues. Seek / write mode was engaged by copying all the files from My Documents in the main HDD to the MX-1. The automatic acoustic management (AAM) on the WD had been already been set to minimum noise using the Hitachi Feature Tool Version 2.04. The seek noise was muted, but slightly more hollow or resonant sounding than when the drive was sitting bare on the desk. Peaks reached perhaps 25 [email protected] It sounded a bit like popcorn popping softly in the distance.

With AAM disengaged, the seek/write noise was considerably louder. It was about as loud with the bare drive as well, but sharper and harder; in the MX-1 it sounded a bit more resonant.

COOLING

In idle mode, the HDD temperature in the MX-1 never exceeded 31°C. After an hour of continuous file transfers and defragging, the temperature rose to 34°C. Just 5~10 minutes after the drive was allowed to rest at idle, the temperature dropped back down to 30°C.

This is impressive performance. Even positioned just behind a 92mm fan spinning constantly at 5V at an open front vent, the data drive on the second PC system idles around 40°C — although this is not directly comparable because it is a different drive from a different brand.

There's no question that the MX-1 provides excellent HDD cooling. Simply placing the WD drive on the floor next to the open PC, powered by the power supply in the PC and connected directly via a long SATA cable, gave these results: 42°C in idle, 44°C after extended load. The improvement in cooling effected by the MX-1 was at least 10°C. Additionally, with the bare drive, the temperature took a long time (over 30 minutes) to drop back down after the period of extended load.

POWER

The electronics and AC/DC adapter of the MX-1 took very little extra power. The resolution of the power meter was a bit too coarse to show it precisely, but the additional power can be estimated to be approximately 2.5W. Most of this power is probably lost as heat during the conversion from AC to DC in the adapter. The PCB in the MX-1 adds almost no heat to that of the hard drive.

TEST SUMMARY: Antec MX-1
Feature
Bare Drive
Drive in MX-1
Difference
Vibration (Horizontal)
4
4
0
Vibration (Vertical)
4
5
+1
Noise: Idle
Noise: Seek (AAM)
Noise: Seek (Normal)
Power: Idle
9W
11~12W
+2~3W
Power: Seek (AAM)
9W
11~12W
+2~3W
Power: Seek (Normal)
11W
13~14W
+2~3W
HDD Temperature
42°~44°C
29°~34°C
over -10°C

 

CONCLUSIONS

The Antec MX-1 is an unusual and welcome external hard drive enclosure. Its combination of features is completely unique: eSATA and USB 2.0 support, along with highly effective active cooling and virtually no increase in noise. The last two qualities make the MX-1 stand head and shoulders above any other external drive enclosure device we know of today. There's really nothing else quite like it.

eSATA makes it possible to isolate the boot
drive
externally, and the MX-1 enclosure could make the drive quieter than when it is installed inside the system. The supplied ~40" long eSATA cable is not quite long enough for us to put the MX-1 in an acoustically padded drawer (with a bit of ventilation) that could eliminate all hard drive noise from your PC. Experimentation is in order.

And although defragmentation and other extended sessions of seek/write modes did show up some mild accentuation of seek noise, in normal use, the acoustics of the MX-1 are determined mostly by acoustics of the drive. Choose a quiet drive, and it will be quiet. But it is unrealistic to put in a noisy beast and expect the MX-1 to subdue it.

The range of options and applications for the MX-1 are varied, like other external storage enclosures. The difference here is that unlike most of them, you need not worry about cooling for your drive and its precious data, and the additional noise will not make you want to turn the thing off ASAP — as long as you choose a decently quiet drive.

If SPCR awarded stars, the Antec MX-1 would get five. It's a great little device. Kudos for Antec's design team for coming up with a landmark product.

UPDATE - June 29, 2008

Occasional comments about the fan in the MX-1 being noisier than described here surfaced in the discussion thread very soon after this article was posted. They were a minority, however, as many reported the similar quiet acoustics we found. Over time, however, the complaints about the MX-1's fan noise have grown. We caution prospective buyers that the production fan might have changed (without any official version change), in which case, our acoustic assessment might no longer be valid.

 



Many thanks to Antec for the opportunity to review the MX-1.

*

SPCR Articles of Related Interest:

SPCR's Hard Drive Testing Methodology

SPCR's Recommended Hard Drives

Icy Dock eSATA external HDD enclosure

Western Digital Caviar SE16 500 GB

* * *

POSTSCRIPT: Google's counterpoint about typical causes of hard drive failures

Discuss
this article in the SPCR Forums.

POSTSCRIPT — April 2, 2007: IS LOW HDD TEMPERATURE DESIRABLE?

An obvious assumption of this review is that high temperature is bad for hard drive health, and that lower temperature is better. The concept is widely accepted in the electronics industry, but a possible counterpoint from Google was brought up in the article discussion in the SPCR forum.

An oft-repeated quote (perhaps originating from Seagate?) is that...

"...increasing HDD temperature by 5°C has the same effect on reliability as switching from 10% to 100% HDD workload. Each one-degree drop of HDD temperature is equivalent to a 10% increase of HDD service life."

This information has a direct corollary in electronics cooling attributed to the US Army. Tony Kordyban, well-known authority on thermal management in electronics, listed the following as item #9 of Ten stupid things engineers do to mess their cooling in the magazine Electronic Cooling:

"Stupid Thing No. 9. Reducing temperature because 'every 10°C drop doubles the life.'

"This is still the gospel of the land. It started with the U.S. Department of Defense Military Handbook 217, which became the standard for electronics reliability. The 10°C rule was part of it.

"Too bad it's not true. Not even the military uses 217 anymore. But like your mom's rule about not swimming for one hour after eating, this rule lives on.

"The alternative is very messy. There are temperature limits that improve the reliability of electronics. But to apply them, you have to understand the physical processes that cause failures in each type of component. That's hard to boil down to a slogan."

If the 10°C rule for electronics is stupid, is the HDD temperature rule also stupid?

A Google study on its servers conducted last year which included over 100,000 hard drives seems to suggest that too low a temperature may have a negative effect on hard drive longevity. The May 2007 issue of Smart Computing magazine summarized the study as follows:

"Google Pinpoints Source Of Hard Drive Deaths

"Why do hard drives fail? In the past, experts have pointed to numerous factors that could contribute to a hard drive’s early (or not so early) demise, but new research from Google shows these conventional beliefs might be inaccurate.

"Excessive usage and high temperatures are often identified as drive-killing culprits, but Google found that these factors might not actually impact drives as severely as previously thought. Instead, the researchers discovered that parameters found in the self-monitoring facility, or SMART (Self-Monitoring Analysis and Reporting Technology), in drives tend to have more damaging potential.

"For example, drives that report higher-than-usual scan errors, which can indicate surface defects, during background scans are 10 times more likely to fail than drives with no errors. Also, reallocation counts, which occur when the drive remaps potentially damaged sectors to a new physical sector, can also contribute to a drive’s death. According to Google, drives with one or more reallocations fail more often than those with none.

"The study collected data between December 2005 and August 2006 from systems across all of Google’s services and included more than 100,000 hard drives ranging in speeds from 5,400 to 7,200rpm and in sizes from 80 to 400GB."

Google's study is downloadble as a PDF here: Failure Trends in a Large Disk Drive Population.

The results of the study are not conclusive with regard to the effect of low temperature on hard drive reliability, but it does raise interesting questions about the generally accepted concept of heat being enemy number one of hard drives. You may want to consider this debate in the SPCR forums started by member (and SPCR author) jojo4u: Google study: effect of temperature on server hdds.

* * *

Discuss
this article in the SPCR Forums.

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