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Silent PC with No Moving Parts

Silent PC with No Moving Parts

A PC without any moving parts has been the Holy Grail of Silent Computing Enthusiasts for years. It's a quest that has led some individuals to fabricate their own cases, massive heatsinks turned inside out, with the components bolted inside them. The Zalman TNN 500 case was the most ambitious commercial realization of this concept, but it is now discontinued, probably due to high cost of production and shipping, low sales volume, and possible reliability issues with the built-in fanless power supply. We've never really been that fond of the fanless concept, simply because a small amount of forced airflow from a good quality fan is essentially inaudible in almost all environments, and its cooling superiority with a good heatsink easily beats even the massive TNN 500. There are also many components other than the CPU or GPU, such as the VRMs on the motherboard, which are best with some airflow for cooling under load.

Still, in special cases, a completely noiseless computer can be useful, perhaps even necessary. Such is the case with SPCR's anechoic chamber, built last summer. The ambient noise level in the chamber is 10-11 dBA, low enough that with the right audio equipment, the noise level of any computer component can be measured and analyzed at standard 1m distance. Such equipment is indeed in place, and the audio analysis equipment can actually measure down to about 9 dBA, below the ambient level of the chamber.

In the past, our carefully built fan-cooled computers were quiet enough to be below the ambient level of the lab most of the time. Now, in the anechoic chamber, these same computers register some 15~18 [email protected], high enough to interfere with the quietest components and computers we've tested. We made do without a computer in the chamber for many months, but increasingly, the lack of a PC in the room became too limiting. Something had to be done. Ideally, we wanted an open-bench system with instant access to all motherboard and power supply connections for quick and easy setup with peripheral equipment or changes on the fly. This meant no component can make any noise, as it really cannot be encased.

The main noise sources in a PC can be divided into two categories: Fans and hard disk drives. There are two others, electronic component noise (such as buzzing from coils and capacitors) and optical drives, but both can be disregarded here. The former is usually at too low a level to be significant or occurs only under very high load, which would not apply with our lab PC, and the other is a component we do not use except to install software. Fans can be eliminated by using a low power CPU with a big passive heatsink, and a fanless power supply. Both Silverstone (Etasis) and Fortron-Source fanless PSUs have proven to be quiet and reliable. The GPU is not an issue here, as we'd be using onboard video.

The hard drive, until recently, tended to set the baseline noise level below which a PC could not go. Yes, there are ways to encase the drive and float it so its mechanical spinning does not translate into audible noise, but these methods make the drive hard to access, and they tend to increase the likelihood of failure. The hard drive has traditionally been more fallible than other components, anyway, despite being the most essential, holding both the operating system and precious data. A solid state drive is the obvious solution, but the cost was prohibitive... until recently.

The decline in prices and improvements in the performance of solid state drives over the past year or two have not gone unnoticed at SPCR. We've been playing with Intel X80-M SSDs for the past six months, and following the trials and tribulations encountered by both users and reviewers with the issue of SSD stutter, their single biggest, most common, sometimes impossible to ignore flaw. Anand of Anandtech has written some massive but insightful reports on this issue (links to Anand's article on SSDs, take 1 and take 2), and as of this date, only three more-or-less affordable SSD lines do not suffer from stutter. The three are Intel, Samsung and OCZ Vertex. Given the usual pricing of these SSDs, it was a shock to discover in March an online store called offering Samsung 64GB and 32GB SSDs in 2.5" SATA form factor for $199 and $139. They were probably overstock items from some corporate OEM order. The Lenovo X300 laptop I recently acquired has a 1.8" 64GB Samsung SSD that's not quite as speedy as I'd hoped, but at such low prices, the offers were irresistible. If the performance was right, the 32GB model would be perfect for a modest low power, open test bed in the anechoic chamber.

Today, the OCZ Vertex SSDs are priced very similarly to the Samsung SSDs I purchased. They are probably better performers. But, given the title of this article, you already know that the Samsung SSDs proved to be fine performers. The 32GB model was used in our first lab PC without any moving parts. The system is perfect for our needs, modest, consuming very low power, and completely noiseless. It is used for hard drive testing, both performance and acoustics, as well as for power supply testing. In the latter role, it runs the digital oscilloscope used to measure AC ripple on the power supplies, and the various spreadsheets used to tabulate power data. At the same time, we use screen capture and other imaging software for those reviews. It will also be used in fan testing.

It doesn't look like much, but it is utterly silent. There are no moving parts except for the floppy; even that's silent once the Hitachi Feature Tool HDD utility is loaded.

Silent SPCR Lab PC Components

Most of the components were on hand, chosen mostly for low power (and low heat) and suitability to the task.

  • Asus M2NPV-VM - older AM2 socket nVidia 6150 chipset micro-ATX motherboard
  • AMD Sempron LE-1300 - modest single core 45W processor, 2.3GHz, 512KB L2 Cache
  • Scythe Orochi - massive heatsink with mediocre mounting not recommended except when motherboard is parallel to the ground as above
  • Corsair CM2X1024-6400 - single stick of 1GB 800 MHz DDRAM
  • Silverstone ST45NF - fanless power supply, overkill for the system but it was on hand and not engaged.
  • Samsung Enterprise SSD MCBQE32G5MPP-0VA - 32GB 2.5" SATA/300 SLC Solid State Drive
  • Mitsumi floppy drive
  • Generic USB wireless IEEE 802.11g adapter

There's really not much to say about the system other than that it is utterly silent and quick enough for the tasks we ask of it. While it is booting up, with my ear within 6" of the PSU, a faint bit of a chattering type of sound can be heard, but once in the Windows desktop, about 40 seconds after the power switch is hit, there is no noise to be heard from this PC. So there are no sound files, no spectrum analysis screenshots, no dBA tables. It runs perfectly cool under normal conditions, and never overheats. Any component is comfortable to touch by hand any time. It draws 53W AC in idle, 41W with Cool 'n' Quiet engaged, and about 80W in maximum CPU load, all of which could be lowered a bit with a PicoPSU and high efficiency power brick, but we're happy with the silence at this point. The big Silverstone PSU also gives us the flexibility of ample power for anything we want to do, including plugging in several HDDs simultaneously. Overall, the cost of the system even with all new components is modest, probably little over $500, and a dual-core 2.6 GHz 45W Athlon like a 5050e would be much more capable and yet have the same thermal envelope with only a minor increase in price.

The Scythe Orochi is huge, and it's used here only because the motherboard lies flat with the weight of the heatsink directly on top. No way we'd use it in a tower case where the heatsink has to hang off the vertical motherboard.

Here is a screenshot taken towards the end of CPU Burn testing. (Click for 1280px width image in a new window.) CPU temperature stabilized at around 61°C after nearly half an hour, in 21°C ambient. The small heatsink atop the Northbridge chip measured around 55°C at this point. All cool enough, but we'll never push the system that hard in lab use. The CPU idles at 37~39°C depending a bit on ambient room temperature.

The Samsung SSD is not only slick and small, it is very light, just 70g.

Manufacture date is 24.04.2008

Brushed aluminum casing all around, standard SATA connections.

HD Tach result on 32GB Samsung SSD.

It is possible to duplicate this noiseless system properly housed in a presentable case. The Antec NSK3480 case comes first to mind simply because it's small, yet wide enough to handle big heatsinks (although probably not the Orochi), and its top PSU chamber with ventilated cover over the PSU makes it ideal for a fanless PSU. The main question regarding thermal management without fans is which CPU, how hard you'll push it, and how often. A 45W CPU is probably the limit, which means AMD X2 45W dual cores are the most capable processors, although perhaps some of the newer Intel 65W dual cores would also work.

With a good heatsink and removal of all airflow impedances at the main case vents, the CPU will be slow to heat up even under load. Even if the CPU temperature exceeds safe levels (say 65°C), if it does so only after an hour of CPUBurn, you have to ask whether you'll ever push the system that hard for that long. Big heatsinks with widely spaced fins like the Thermalright HR01 are the only suitable ones for fanless operation. However, introducing a single quiet fan on the heatsink to run at under 500 RPM would get you 99% of the silence and much better cooling at load. The ambient noise in your room and distance between you and the PC would probably make than fan inaudible. A discrete graphics card faster than the 780G onboard is probably out of the question without a case fan... but you could try experimenting with modest, fanless cards with massive heatsinks.

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Articles about fanless and otherwise silent store-bought systems:

mCubed HFX Micro S13 system: Atom 330, Silenced

Anitec's SPCR-certified SilenT3 PC

Apple's 24" iMac: There's more to High End than Performance

Puget Custom Pentium-M Rig: A Silent WC System

Fanless Ultra Powerhouse PC (TNN 500) by EndPCNoise


DIY fanless systems:

Bill's Recycled, Fanless, Silent Woodbox Computer

Fanless Heatpipe Cooled System by FMAH

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Discuss this article in the SPCR forums.


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