Is the Silent PC Future 2.5-inches wide?

Storage

March 8, 2004 by Mike Chin

The silent future is 2.5" wide, I announced in a SPCR Forum post at the end of January. I was referring to the future of silent computing, and to my recent discovery of extremely quiet notebook hard drives that easily put the quietest of 3.5" desktop drives to shame. Forum member "Al Bundy" eagerly chimed in:

Welcome to my world Mike! I've been trying to get folks to try using these recent notebook drives (with IDE adapters) for a little while now, especially the 8MB cache versions. Forum member aderyn was the first one I read about here that did this, which inspired me. They really are the quietest option IMO (other than solid-state).

Interestingly, an announcement from Seagate at the Intel Developers Forum in San Francisco just a couple weeks after the above forum thread got started made me realize my announcement was too limited. It appears that there is a move to 2.5" drives on the enterprise computing side as well, and this move will likely mean the 2.5" drives will appear alongside 3.5" desktop drives in the near future. The Feb. 17 announcement was about the Savvio, a 2.5 inch enterprise disk drive. I quote the most salient parts of the long Savvio news release:

SAN FRANCISCO, Calif.—17 February 2004— Reinforcing its position as the disc drive industry's leading provider of innovative storage products and technologies, Seagate today introduced Savvio, the world's first family of 2.5-inch enterprise-class disc drives...

...In addition to its fast 10,000 rpm spin speed, the Savvio disc drive has an impressive reliability specification of 1.4 million hours MTBF. And unlike MTBF testing for ATA and SATA disc drives based on desktop-environment conditions, Savvio's reliability rating is specified based on testing in a 7/24/365 100% duty cycle enterprise-class workload environment...

The Industry Shift to the 2.5-inch Enterprise Standard
Seagate examined end-user IT challenges and determined that server storage consolidation as well as reducing data center space were significant priorities that required further attention at the enterprise level. Seagate initiated the move to the 2.5-inch platform as a solution to these challenges and formally announced this move in May of 2003 with the support of HP, Intel, Microsoft and others...

"Space and power are increasingly regarded as corporate assets that must be managed and preserved, and more and more users are demanding that servers and storage systems take up less physical space and consume less power," said John Monroe, a research vice president at Gartner. "New breeds of 2.5-inch high-performance drives will enable evolving enterprise systems to deliver enhanced speed and reliability while reducing power and space requirements. The shift to a new enterprise HDD form factor is inevitable and inescapable. Gartner predicts that 2.5-inch enterprise-class drives will be the predominant HDD form factor in multi-user environments in 2007."

Savvio 2.5-inch, 10,000 rpm disc drives offer a number of advantages over 10,000 rpm 3.5-inch drives including: size (70% smaller); weight (1.12 lbs less); power (40% lower); drive seek time (15% faster); interface (3 options - Fibre Channel, Ultra320 SCSI and SAS); and reliability (1.4 million hour MTBF). These advantages translate into system level benefits never before seen in a 10K drive.

Checking the technical specifications of the Savvio, there's no question of its high performance, with average seek time of 4.1 ms (plus 3 ms latency) and data transfer rates up to 752 Mbits/sec, amazing performance numbers that approach those of the Cheetah 15K.3 15,000 rpm drives. Acoustic output at idle is stated as just 2.4 Bels, similar to the 2.5 Bel of the much slower 2-platter Seagate Barracuda ATA V 80G desktop drive and a whopping 0.7 Bels quieter than the quietest version of the Cheetah 15K.3 drive.


8 MB cache 5400 RPM Seagate Momentus 2.5" drive was an industry first.

When you consider the above with info about Seagate's 5400 rpm Momentus 2.5" hard drive, it's clear that Seagate is very serious about 2.5-inch drives. As the dominant manufacturer, Seagate's push to 2.5" drives will reshape the hard drive industry.

FIRST HAND: 2.5" vs. 3.5" DRIVES


Toshiba notebook drive dwarfed by 3.5" Samsung.

Moving down from big industry developments to our own quiet little backyard, I want to tell you about some experiments and measurements with hard drives I've been doing recently. These include several notebook drives as well as a Seagate Barracuda IV 40G (still SPCR's 3.5" quiet reference but discontinued) and a Samsung SP0802N, now my personal HDD of choice in the lab and in new PCs that I build.

First of all, a summary of each drive examined here:

Hard drive model
Size
Cache
RPM
Capacity
Power*
Seagate Momentus ST94811A
2.5"
8 MB
5400
40GB
2.87W
Fujitsu MHT2040AT
2.5"
2 MB
4200
40GB
2.1W
Toshiba MK4025GAS
2.5"
8 MB
4200
40GB
2.6W
Seagate Barracuda IV
ST340016A
3.5"
2 MB
7200
40GB
13W
Samsung SP0802N
3.5"
2 MB
7200
80GB
8.6W

* Power consumption during write. Max power is at turn on, and about double this, but lasts only a few seconds.

FrontierPC, a SPCR sponsor and Vancouver retailer with an online shop, deserves much thanks for kindly providing loaners of the Seagate Momentus and Toshiba notebook hard drives. (Certainly if you are a Canadian or a Vancouverite, I recommend you pay FrontierPC a visit. They have recently moved to larger premises just a few doors from their old West Broadway location.)

Aside from the big differences in rotational speed, power consumption stands out dramatically. Many of you already know from other articles on SPCR that the Seagate Barracuda IV has always been a hot operator and that the Samsung is substantially cooler. The power number give clear evidence of that. Note how low the notebook drive power consumption is. Not one even reaches 3W. They run cool to the touch.

Because of the exceedingly low thermal output, it's easy to think about putting the notebook drives in acoustic isolation chambers or boxes, or even the Silent Drive, without causing any significant temperature rise. This is an experiment I did not have time to pursue. Perhaps in a future article or update.

The above drives were placed bare, one by one, on a small light side table that stands about 18" off the carpeted floor. The room is basically an ordinary living room that measures 20 x 12 feet, with an 8' ceiling and acoustics that represents a balance between very lively and completely damped. An IDE drive adapter was used to power each drive with a fanless PSU, the TKPower 300 used in John Coyle's VIA C3 system.

A highly accurate calibrated B&K model 1613 sound level meter on loan from the University of BC's acoustics lab was used for noise measurements.

This professional caliber SLM dates back to 1978, weighs over 10 pounds, and is completely analog in design. It has a dynamic range that spans over 140 dB. The microphone has a 1" diaphragm that's very responsive to low sound levels and low frequencies. The unit's absolute sensitivity reaches below 0 dBA: I have seen it read -4 dBA in the midband (1kHz) for background noise in the UBC anechoic chamber.

For the measurements, each drive was placed on its side, leaning a bit against a heavy thick dictionary to keep it stable. The microphone of the SLM was placed 1 away, at the same height as the drive so that it read directly off the large top surface of the drive. I found that if the HDDs were allowed to rest flat on the table, and presented its side edge to the mic of the SLM, the noise actually dropped 1~2 dBA. (This may be useful info for those who want to tweak HDD position for lowest possible audible noise.)

The measurements were conducted after midnight on a weekday. The room ambient with no noise sources in the room (other than my breathing a few feet from the test mic) was ~14 dBA.

Only the idle noise was measured, because there was no easy way to completely silence a boot drive for a system in the same room. Each drive would have to be connected to a system in order to seek; and the boot drive of that system would interfere with the extremely low noise levels being measured here. I could have disk-cloned a Window XP installation on all the drives, and used each as the boot drive in the same system, but I just did not have the time. Again. it will have to wait for a future update. However, as I plugged each of these drives into an operational PC system for listening and general use, I will comment on the subjective noise.

HDD NOISE
Idle*
Subjective notes & Seek noise
Seagate Momentus ST94811A
24
The Momentus has a terrible constant "pure" tone somewhere in the 6~10KHz range. It drops 2-3 dBA in level when the listener or the mic faces the edge of the drive because of directionality of the high frequency whine. Seek noise is substantially higher, probably 3~4 dBA. Vibration is much lower than any 3.5" drive, but higher than either of the 4200rpm drives tried. A real disappointment, but it did perform about as fast as or faster than the B-IV.
Fujitsu MHT2040AT
16
The only noise maker in the Mappit A4F PC, which seemed virtually inaudible to me. The noise is not inaudible, but very low and soft, easily dismissed in the ambient noise of all but the quietest spaces. There is no high pitched whine to speak of, and the seek noise does not seem more than maybe 2 dBA higher than idle. It is the slowest performer of all the drives here. Extremely low vibration.
Toshiba MK4025GAS
16
This 8 MB cache 4200 RPM drive offers 30% better performance than 2 MB cache 4200 rpm drives, and identical in both idle and seek noise to the Fujitsu above. Extremely low vibration.
Seagate Barracuda IV
ST340016A
20
In idle, it remains the quietest of all 3.5" drives. This sample is almost 2 years old, but seems unchanged in noise. There may be a touch of high frequency whine but it is very low in level, and easily obscured when mounted in a PC case. Seek is considerably higher, possibly as much as 5~6 dBA. Low vibration, but MUCH higher than any of the notebook drives.
Samsung SP0802N
21.5
The idle noise is a touch higher, and its seek may actually be lower than the Seagate B-IV. Similar vibration level as the B-IV.

* dBA @ 1 meter

NOTE: The Seagate Barracuda IV and a Samsung SP1602N (which has the same sonic signature as the SP0802N) were reviewed along with an IBM/Hitachi 180GXP in this earlier article, Quiet HDDs by Samsung, Hitachi & Seagate.

CONCLUSIONS

It is possible that the pure high frequency tone emitted by the Seagate Momentus could be cured by the use of a drive isolation box. Many SPCR readers who have read through the forums will have some idea of various ways of building such a box. Both the Smart Drive and the Silent Drive HDD enclosures could probably be employed with these notebook drives to achieve substantial noise reduction, perhaps as much as 5~6 dBA or more. Because of the very low vibration level of the notebook drives, mechanical decoupling by elastic or viscous mounting methods may not even be necessary. (NOTE: Adapters are available to mount notebook drives where 3.5" drives would normally go.)

In contrast, the Seagate and Samsung 3.5" drives, among the quietest ever made, always require mechanical decoupling to achieve the lowest noise. When firmly mounted in the conventional way with screws, the vibrations from the 3.5" drives get transmitted into the chassis, and always create at least a small degree of humming or other low frequency noise. Conduction can even amplify high frequency noises effectively.

In this mix of drives, the Toshiba MK4025GAS emerges as the best silent choice. With the 30% boost of its 8 MB cache, performance is at least at the level of standard 5400 RPM drives, and the level of noise and vibration are both exceedingly low, lower than most any noise source you are likely to have in your PC. My guess is that most similarly equipped 4200 RPM will be close in both noise and performance, but testing of other drives is needed to verfy this.

There is a price and performance premium for notebook drives: Typical 40GB notebook drives sell for double the price of 40GB 3.5" HDDs -- if and when they are available. 60G or 80G is the smallest 7200 RPM desktop HDD size available these days, and they start at as low as ~US$70. All will easily outperform a 2 MB cache 4200 RPM notebook drive.

Still there's no prospect of sub-10 dBA performance from any desktop hard drive; there is with notebook drives. We'll see whether sub-10 dBA is really possible in our next article about notebook drives. Stayed tuned in!

* * *

Much thanks to FrontierPC for the loan of the Seagate and Toshiba notebook hard drives.

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