In the three years since an overview of Acoustics in the PC industry was posted here at SPCR, much has changed. Performance-per-watt, Mobile on Desktop, high efficiency dualcore processors, the 80 Plus PSU program, Entertainment PCs and a new Energy Star spec for computers are all converging to suggest a quieter, cooler future is not far away. Our observations, analysis and conjectures on the current state of the quest for quiet computing.
March 17, 2006 by Mike Chin
Concern about computer noise was expressed only by a tiny segment of power users back in 2001 when SPCR was first conceived. These were people who worked around computers constantly and ? whether by natural disposition and sensitivity or by over-exposure ? were bothered by the noise of screaming hard drives and fans. There may have been others who didn’t like computer noise either, people working in offices, or innocent bystanders sharing living space with die-hard gamers and their noisy PCs, but they were rarely vocal. Even when they were, no one seemed to hear them.
Today, in March 2006, SPCR is nearly four years old and gets some half million unique visitors every month. An interesting aspect of our traffic is that the geographic distribution of our visitors perfectly reflects the online populations in the world. We interpret this to mean that the interest in quiet computers crosses all boundaries. SPCR is no longer the only web site to pay attention to acoustics in computing gear. Many other hardware review web sites at least mention noise in some of their reviews, and some take it quite seriously. Still, SPCR is almost alone in our systematic and holistic approach to assessing PC noise, not only measuring but analyzing closely with our own ears and recording the sounds for readers to hear for themselves.
We still listen.
NOISE AND HEAT
Very early in our history, SPCR made the undeniable connection between PC noise and thermals. Expressed simply, it goes like this:
- Much of the noise produced by a computer comes from the fans.
- The fans are necessary to cool hot components and to evacuate the hot air from the computer.
- The hotter the components, the faster and louder the cooling fans must run.
- An obvious way to reduce noise is to slow down the fans, but in order to do so safely, the components must generate less heat.
- The less heat there is in the computer, the easier it is to make it run silently.
These simple observations form the basis of much of the content of SPCR, from the reviews to the advice routinely dished out in the forums. There are many fine nuances and extensions of the silencing mantras, but it’s not astrophysics.
HEAT & POWER EFFICIENCY
When we examine thermals and power, things get a little more complex. In general, the amount of power consumed by an electronic device is equal to the heat it generates. Hence, the power consumption of a PC measured at the AC socket tells us how much heat is in the box. This is complicated by the fact that whenever electrical energy is transmitted or converted (from AC to DC), losses occur. Inside the PC, losses occur when:
- The AC is converted into DC within the power supply. (The power supply provides three DC voltages: +12V, +5V and +3.3V.)
- The 12VDC is converted by the voltage regulation module on the motherboard into yet lower voltages for the CPU (typically <1.5VDC).
The most efficient power supplies (PSU) for PCs have an AC/DC conversion efficiency of >80%. The most efficient VRMs on desktop motherboards may approach 85%. This means that from the AC to the CPU, the best power efficiency is no better than about 70%. Both the PSU and the VRM are much less efficient at higher and lower power levels ? including idle, which is where most computers operate 95% of the time. So perhaps a realistic AC-to-CPU energy efficiency figure is about 60%. This means, for example, that a CPU requiring 30W at idle actually draws 50W at the AC socket. The remaining 20W is lost as heat inside the PSU and on the motherboard VRMs. Of course, the 30W that does get delivered to the CPU also ends up as heat, which has to be dissipated with the help of a heatsink and fan.
In recent years, there has been increased attention on improving the efficiency of the power supply. SPCR played a small part; we were the first PC hardware site to analyze and report PSU efficiency, initially as an adjunct to acoustics, but increasingly as an item of interest all on its own. We still remain one of the few hardware sites that analyzes PSUs with any seriousness. The 80 Plus program to certify and encourage the use of high efficiency PSUs by system integrators, and the rising standards for efficiency in the widely accepted Intel-driven ATX12V (and other form factor) power supply specification have helped to increase awareness of the benefits of higher power conversion efficiency. It would seem that power supply efficiency remained virtually unchanged for the first couple decades of the PC’s history, but in the past couple of years, the average efficiency of higher priced models has improved dramatically.
Noise remains tied to heat.
PERFORMANCE PER WATT
All of this is good and fine, but the main sources for high energy consumption and heat in the PC are still the CPU, and especially in the last two years, the GPU (graphics processing unit). Leaving the latter for the moment, CPUs have become steadily hotter over the past couple of decades. There has been a direct correlation between computational performance and heat. The speediest 386 CPU made by Intel back in the mid-late 80s ran at 33MHz and produced less than 2W of heat. It was usually cooled with a little piece of extruded aluminum barely an inch square. Today, the hottest desktop processors from Intel have an official TDP of 130W and have been measured to draw as much as 160W by third party reviewers. Desktop processors from AMD are cooler, topping out at a realistic 110W. These numbers are a long way from <2W.
The decades-old clock speed race which caused such escalations in CPU power demand finally ended in October 2004 when Intel announced it would not seek to reach 4 GHz clock speed for its Pentium 4. Leakage losses and ever escalating thermals spelled the end of further development of the P4 core, and Intel shifted strategy to uphold multi-core processing as the new path to computational nirvana. (By then, Intel’s closest competitor, AMD, had already introduced the Athlon 64, which was outperforming faster-clocked, more power hungry P4s, and had the benefit of 64-bit capability implemented as an extension of x86 architecture.)
Intel has been promoting the concept of performance-per-watt since the Fall 2005 Intel Developers Forum (IDF). They are not alone in this endeavor; the rest of the industry has already been focused on this concept for some time. Ashlee Vance, writing about last week’s Spring 2006 IDF for The Register, says that finally, Intel’s talk starts to match rivals’ products. Mr. Vance presents his case with withering sarcasm, opening with the following lines:
“You have to hand it to Intel for talking about power management and the benefits of multi-core processing with such confidence. Using reality distortion, Intel has convinced itself that it pioneered such technology instead of being the lone laggard to catch up with the rest of the industry.”
The rest of the article documents sharply how Sun Microsystems, IBM, and AMD have been ahead of Intel in multicore processors, power efficiency, and “green computing” matters. As a point of fact, on January 31, 2006, Sun, AMD, HP and other companies teamed up with the EPA’s Energy Star to sponsor a Conference on Enterprise Servers and Data Centers: Opportunities for Energy Savings.
The salient fact for SPCR is that with Intel finally in line with its competitors, power efficiency in computing is where it should be: Smack dab in the center of engineering objectives for all the players who make processors. AMD processors are already quite efficient, with rated Thermal Design Power dropping steadily as they introduce new steppings (versions) of Athlon 64 single and dual models; their real TDP is often just half that of comparative current Intel desktop processors. Intel promises a dramatic reduction of power and improvements in performance in their Conroe desktop processor, due to become available in the third quarter of 2006. AMD, always more conservative about future product revelations, has indicated that new Athlon 64 X2 models slated to be released in Q2 this year in their forthcoming AM2 socket (with DDR2-800 support) will be more than competitive with Conroe’s performance and target 65W TDP. Their Turion 64 X2, also slated for Q2 release with dual-channel DDR2 support in a new socket called S1, will be directly competitive with Intel’s Core Duo processors. So it seems that a phase of cooler and quieter CPUs from AMD and Intel is assured for the near future.
MOBILE ON DESKTOP
Intel’s first power-efficient desktop products came from partners AOpen, DFI, and Shuttle, who offered desktop boards and systems for the Pentium M, till now considered a mobile processor. A new term has been coined for this type of product: Mobile on Desktop (MoDT). Now, Intel has redefined its Pentium M and latest offshoot Core Duo and Core Solo processors as suitable for both desktop and mobile processors. Again, the first to make use of the latest high efficiency Intel CPU is a partner ? this time, Apple, who is using the Core Duo effectively for an extremely quiet integrated computer, the iMac. The 17″ and 20″ LCD iMacs have rated SPLs of just 20 and 22 dBA at a distance of approximately 60cm. (See our User’s Review of the 20″ iMac.) Such low noise is simply not feasible without the low power Core Duo processors used in these new iMacs. We are aware of several Core Duo MoDT products being prepared by Intel partners AOpen, Asus, Shuttle and probably DFI. There could well be many others we are not aware of.
Soon to come i975Xa-YDG MoDT board from AOpen: Core Duo support
with dual PCIe-16 slots.
Then there is the tiny power-efficient mini-ITX platform, which continues to expand. VIA, the creator of the m-ITX platform, finally has the long awaited fanless, even tinier nano-ITX products in the market, as well as new C7 processor-embedded m-ITX board running at 1.5GHz and 1.2 GHz. Others using VIA C7 processors (at up to 2GHz clock speed) for m-ITX boards now include big names like MSI, Gigabyte, Samsung and DFI, to name just a few. AOpen, expanding its MoDT product range, has brought Intel Core Duo / Solo to the m-ITX platform with several new boards shown at CEBIT 2006. (For detailed, dedicated coverage of mini-ITX, please visit www.mini-itx.com.) The power demands for most of these systems will probably be under 30W in idle mode.
All of these various developments dovetail nicely with the new voluntary computer specification for the US Environment Protection Agency’s (EPA) Energy Star program that is coming into effect in 2007. SPCR published an extensive article on this development a year ago when it first came to light: A New Energy Star… in 2007.
Currently, the Energy Star specification for computers, integrated computers (such as the iMac) and monitors is not demanding. It only specifies what AC consumption should be while in sleep mode during which as much as 10% of the included PSU’s power rating is allowed to be consumed. The proposed revision introduces power consumption targets while the computer is actually powered on and running. The latest draft of the revision, which has changed since the article linked above, was discussed at a stakeholder meeting hosted by the EPA on February 15, 2006 in Washington, D.C.
Here’s a partial summary of the power requirements of the proposed Energy Star spec discussed at that meeting:
Summary of ENERGY STAR Program Requirements for Computers
Draft 1, version 4
1) Desktop / Multimedia Computers
Standby (Off Mode): < 2W
2) Integrated Computer Systems
Standby (Off Mode): < 3W
3) Notebook Computers / Tablet PCs
Standby (Off Mode): < 1W
Standby (Off Mode): < 2W
5) Power Supplies
— Internal: For all of the above system categories, if an internal power supply is used, it must have 80% minimum efficiency at 20%, 50%, and 100% of rated output and Power Factor of > 0.9 at 100% of rated output. This is identical to the 80 Plus certification requirements. The PF spec is only possible to meet with Active PF correction.
|*The desktop / multimedia PC category has been divided into basic and high performance. This was requested by the industry to reflect the huge range of PC performance in the marketplace. Currently, the definitions are simple: Any PC with dual processors, a multicore processor or a single-core processor clocked higher than 2.7 GHz is considered high performance. Single core or single processor machines with clock speed lower than 2.7 Ghz are considered basic performance. Obviously, these definitions need refinement, as admitted by Energy Star staff; they are starting points. The role of graphics cards needs to be accounted for, and CPU performance cannot be simply correlated to clock speed, especially when comparing different processor lines, even from the same company.|
The 49W and 74W idle targets for desktop / multimedia computers are quite aggressive. There’s no question that the vast majority of desktop computers sold today cannot meet the idle power limit of 49W AC for basic performance models. However, with some adjustments, including the use of a high efficiency power supply, most current MoDT PCs, and minimalist systems running AMD Cool’n’Quiet engaged processors without high power graphics cards could probably comply with this demanding low idle power requirement.
The proposed Energy Star computer spec is slated to go into effect on January 1, 2007, but there is talk of pressure from the industry to delay the date to July 1, in order to give all the players adequate time to get ready. It’s rumored that Dell and HP already have prototype Energy Star models that comply with the desktop spec, and they want the additional time to try and obtain required components at minimal or no additional cost (compared with current non-compliant parts). The efficient power supply is likely the single most significant cost. Once the new spec comes into effect, it’s likely that all US government agencies will be required to seek Energy Star compliant products for their IT purchases. Schools, hospitals and other enterprises are likely to follow suit for savings in energy cost. This represents a very sizable market.
Certainly, not all PCs will meet the new Energy Star spec. The EPA anticipates that some 25% of products will be compliant, compared to 98% of computer products with the current much less stringent spec. The Energy Star marque will then be meaningful for consumers of computer gear rather than just a ubiquitous rubber stamp. The marque will identify high energy efficiency computers. If the price difference is small, the typical consumer will choose an Energy Star PC over one that is not certified. Certainly, when the new Energy Star spec comes into effect, consumer awareness about energy efficiency in PCs will rise.
RUNAWAY GPU THERMALS
The realm of graphics cards and gaming PCs is truly horrid at this time, from the point of view of noise, thermals and energy efficiency. The problem is with graphics card makers ATI and nVidia, who have raised the thermal / power envelope of their top GPUs well beyond the 100W mark. With SLI and Crossfire, they have pushed the thermals beyond that of the hottest CPU. Two graphics cards each radiating in excess of 100W, just a few centimeters from each other ? there is little hope for such a setup to be even remotely quiet or energy efficient. Passive midrange cards are getting fewer and farther between, and worse, the tech press seems to encourage it. For every midrange or low-end graphics card roundup, there are a dozen unrealistic high end comparisons that worship the success of ATI / nVidia in setting some new record on some random benchmark.
This is not to dismiss the recent efforts of some brands in offering fairly high performance passively-cooled graphic cards. Asus has been very active in recent months, with a growing range of innovative, cleverly implemented passively cooled graphic cards. Gigabyte also has quite a range of passively cooled cards. There are many aftermarket passive and quiet heatsink mods from Zalman, Arctic Cooling, and Thermalright, to name just a few, and these products can help tame the noise of some graphics cards, but never the hottest and fastest. They cannot change the massive heat dissipation that’s at the heart of the problem. A sign of the times is Sapphire‘s new Blizzard Radeon X1900XTX card, which utilizes a miniaturized liquid cooling system for quiet operation.
The future looks bright for quiet computers. Dramatically improved power efficiency in processors and power supplies, and a broad trend towards performance-per-watt as the key industry benchmark bodes well for improved thermals in computer gear. Extremely quiet off-the-shelf computers such as the new Core Duo powered iMacs will probably become more commonplace. In time, the average PC may become quiet enough for the average user. With increasing exposure to quieter machines, consumer awareness of PC acoustics is bound to rise, and demand for quieter computers will be greater than ever.
The trend towards quieter computers will be especially apparent in the entertainment PC arena. Entertainment PC technologies have finally matured and appear capable of delivering on their early promises. As computers move into living rooms and dens, consumers will increasingly demand low noise as a fundamental requirement.
We have not discussed the other main source of noise in PCs (other than fans), the hard drive. Suffice it to say that while the very quietest desktop HDD of four years ago was actually slightly quieter than the quietest desktop model available today, industry-wide adoption of the Fluid Dynamic Bearing has led to a dramatic lowering of HDD noise from all the manufacturers. Furthermore, a growing number of even quieter 2.5″ notebook drives in ever higher capacity with desktop-compatible SATA interface has expanded options for quiet PC builders. (See the Storage section of SPCR for more details.)
There are other areas where improvements in power efficiency are needed. For example, the efficiency of most VRMs on motherboards plummets way below 80% when the CPU power demand drops down to the <20W levels required to meet the 49W idle power Energy Star spec. Actually, CPU power needs to be more like <10W, and VRM efficiency at that point is usually below 60%. As the industry responds to the challenge of Energy Star, we can probably expect specialized MoDT motherboards to improve VRM efficiency at low power levels. And even though there will probably quite a few PSUs that can meet the 80 Plus spec soon, we would welcome further improvements in power supply efficiency, perhaps approaching 90%, if it can be done without exorbitant cost.
One sometimes wonders if the GPU power race will ever stop, but it is salient to remember that Intel hit a wall with CPU clock speed increases and thermals. There’s no reason to believe that GPUs can continue getting hotter indefinitely. Perhaps a move to multicore GPUs could trigger interest in higher efficiency. Perhaps the desire to obtain Energy Star approval will spark a change. It is also worth noting that extreme gaming machines are few and far in between, despite the marketing efforts of the graphics card makers and the obsession of gaming hardware review sites. The prohibitive cost of the hottest graphics cards is enough to keep them out of the reach of all but the most fanatical gamers.
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