Building a Silent PC: My Quest for Quiet

Chapter 4: Need for Speed

Terry Gray

Original: 16 Jul 2003
Initial draft; work in progress

2GHz or Bust

All of us have moments of weakness. When an aging system in my computing menagerie needed to be replaced last December, I first thought that another Pentium III system would be in order. But I noticed that P4 processors were now actually less expensive than P4 processors, not to mention reputedly faster. Moreover, I found that it was very difficult to find socket 370 (P3) motherboards with contemporary features such as USB2 and firewire. Hence, I decided to succomb to the siren song of fast CPUs, and see whether a P4 system could be made acceptably quiet.

Processor Choice

I've always steered clear of AMD processors for quiet computing because of their reputation for high-heat output. Some say that reputation is not deserved, but I decided to stay with Intel and use 130nm Northwood core P4 processors for my speedy systems. These are generally considered to be pretty "cool running" chips. I would recommend the slowest P4 that supports the 533MHz bus, which means 2.4GHz.

Processor Cooling

The "best practice" idea is simple: get a really good heatsink and put a quiet 12 volt fan on it that is undervolted to 5v --at least during routine/low-demand computing tasks. Note that the effectiveness of heatsinks varies with air flow and design: some work better at low air flow levels than others do. Check out for current recommendations.

Power Supply Redux

There are more fan-free power supply options available today than when I built my first silent system back in 2000. At the high-end, there is an excellent power supply made in Germany, the SilentMaxx proSilence PCS-350. This unit is pricey (US$235) but (unlike the TKpower unit I used for my Pentium III system), it is P4 compatible and comes in a conventional ATX form factor --though minor trimming of the case cutout may be needed on some cases. In the USA it is available from Silicon Acoustics.

For small P4 systems (needing on the order of 100W) a new fan-free power supply option comes from The 100+ watt version for P4s has just been released; they also make a 60W version for really low-power systems, such as the VIA EPIAs.

There are also now more choices for relatively quiet power supplies with fans. Some recent models use a (single) large (120mm) fan. The idea is that the larger fan (80mm is typical) allows the fan to rotate at a lower speed, and thus, operate at a lower noise level. Fotron is one manufacturer getting some good press for this approach, but I have no first hand experience with how quiet they really are.

Some vendors have decided (recognized?) that quiet computing enthusiasts represent a specialty market with zealots willing to pay absurd prices. (Think high-end audio for a comparison.) Putting an inexpensive temp controlled fan circuit into a $50 power supply turns it into a $100 power supply. I can see paying a premium for a well-engineered fan-free power supply with massive heat sinks (like the SilentMaxx) but slowing down the fan and doubling or tripling the price sure seems like gouging.

Disk Drives

I'm not aware of any recent breakthrus in disk drive noise, but my sense is that the advent of fluid drive bearings a couple of years ago really did change the industry. Recent drives I've purchased are certainly quieter than those I purchased four years ago. On the other hand, reviews of some of the latest models report higher noise levels than the "Gold Standard" Seagate Barracuda IV.

To Standby or Not to Standby

Maybe it's just me, but I've had a lot of trouble finding motherboards that can reliably go into S3 (Suspend To RAM) standby mode, and reliably come out of it! Sometimes the symptom is that the screen doesn't "wake up" even though there appears to be disk activity etc. Of the two Intel 845-based systems I built, the AOPEN mobo handles STR well, but the ASUS mobo does not.


Fancy Mobos with fan control. The AOPEN mobo comes with a fancy mechanism for software and sensor control of fan speed. There are some issues with whether the fan state survives the board going into standby mode, but the main observation I made is that having fan speed change as temperatures change sounds like a perfect solution, but can often be more annoying than having fans run at a constant speed. On the other hand, most of the time we can get along with a low fan speed, but for some tasks we need more cooling. Perhaps it is a matter of tweaking the controls so that the speed doesn't change very much, only when there is a significant and persistent load/temperature change.

One disappointing trend I've seen on the latest motherboards is fans on Northbridge chips! We've already seen this trend for awhile on high-end video cards, so it is troubling to see yet-another-fan being added to the normal system complement. Yes, the new Northbridge chips do a lot more than older ones and are subject to the same physics as CPUs, but it is still depressing to see this happening.

On the other hand, there is acoustic innovation in small-form-factor systems. Most notably, the use of heat pipes and cases as heatsinks. One well-publicized example is the HUSH PC from the U.K. There is also now a small-form-factor case designed for convection cooling. See Let's hope the growing interest in quiet PCs will foster even more such choices.

This is one of a series of articles describing my silent computing adventures. This link will take you to the beginning of the story.