Faster, Quieter, Lower: Power Consumption and Noise Level of Contemporary Graphics Cards

It is no secret that as the contemporary graphics cards get more powerful and hence require better quality power supply units and more efficient cooling systems. Power consumption and the level of generated noise very often become other important criteria besides performance and image quality when one is shopping for a graphics accelerator. Today we will try to find out what VGA cooling solutions are the quietest and the loudest ones, and what contemporary graphics cards can be called the most economical from the power consumption standpoint.

by Alexey Stepin , Anton Shilov, Yaroslav Lyssenko
07/30/2006 | 02:54 PM

About half a year ago we last performed a comparative test of power consumption of graphics cards (for details see our article called The Grand Clash for Watts: Power Consumption of Modern Graphics Cards). A lot of new exciting products that set new performance records have been released since then. We now pay more attention to the noise characteristics of graphics cards because their ever-growing power consumption calls for more and more complex cooling systems with faster and louder fans.

 

Fortunately, cooling technologies have also been developing theoretically as well as practically, so we do hope that despite the growing appetites ordinary PCs won’t reach the noise level of a vacuum cleaner or a hair-drier.

For example, a few years ago they used to make thick-ribbed and large heatsinks from ordinary anodized aluminum and capped them with high-speed fans to improve cooling efficiency. Today, passive coolers with thin ribs, copper bases, heat pipes and combinations of the mentioned technologies are getting widespread. And so, the increasing power consumption of graphics processors shouldn’t make computers much noisier.

The downside of this growing complexity of cooling systems is that the manufacturers sometimes try to reduce the cost of a product by installing something simpler and cheaper on it. As a result, a graphics card with low power consumption may prove to be rather noisy at work.

In this article we will examine the power consumption of present-day graphics cards and will also check how noisy they are.

Cards We Play With

So, power consumption is indeed an important factor, but not the decisive one. Besides pure performance and desired architectural features, one has to pay attention to a whole lot of other physical factors like those we mentioned in our previous article on this topic. Here they are:

In this review we focus mostly on power consumption in various operating modes and on the level of noise, but we will keep this list in our mind and stress any good or bad points of a particular product according to it.

Power Consumption Measurements: Testbed and Methods

In our reviews we use a digital multimeter Velleman DVM850BL (0.5% accuracy) to measure the current on different power lines. The testbed is configured like follows:

We use the same methodology since 2004 (for details see our article called Power Consumption of Contemporary Graphics Accelerators. Part II: NVIDIA vs. ATI) and think it has proved its worth: we measure the current in shunts that we connect into the +3.3V and +12V power lines of the mainboard’s graphics slot. Similar shunts are also connected into the alternate power connector (the additional power connector on the graphics card’s PCB).

According to the PCI Express x16 1.0a specification, up to 72 watts of power can be transferred through the +12V lines of the mainboard as well as through the additional power connector, i.e. 144 watts in total. Additionally, some power can be consumed from the mainboard’s +3.3V line (this line is used to simplify power conversion for some chips on the graphics card). It means that a modern graphics card cannot have a power draw of over 150W, at least mainboard and PSU manufacturers make their products basing on that supposition.

Some of our readers inquired after the distribution of power consumption among the different lines and we do offer this information for some of the tested devices. These numbers aren’t, however, important for certain products, so you should excuse us for not giving you this information for every tested graphics card.

We created the Peak 3D load by launching the first SM3.0 graphics test from 3DMark06 and running it in a loop at 1600x1200 with enabled 4x full-screen antialiasing and 16x anisotropic filtering. The Peak 2D load was created by means of the 2D Transparent Windows test from Futuremark PCMark05. In the Idle mode the graphics card was displaying the Windows XP Desktop.

Noise Level: Testbed and Methods

The level of noise produced by graphics cards is measured in our labs on the computers that we use as the testbeds for benchmarking the same cards.

We employ a digital sound-level meter Velleman DVM1326. This instrument has a resolution of 0.1dB and allows measuring noise level in a range up to 130dB with A or C weighting.

We minimize the influence of external factors by performing the measurements at night and with closed windows; the background noise level is about 36dBA then. The sound-level reading is about 40dBA at a distance of 1 meter from the test platform when a graphics card with passive cooling is installed in it. These are the two reference numbers we base our judgments upon. The noise is measured when the system case is open.

Just like when measuring the maximum currents, we check out three operating modes – Idle, Peak 2D load, and Peak 3D load – which are described in the previous section.

Premium Graphics Cards

Power Consumption

Today, all premium-class graphics cards support a dual-link DVI interface, thus permitting to connect large monitors, including models with a diagonal of 30”. Such cards also have similar dimensions. They are all rather long and occupy two expansion slots, so you need a rather roomy system case to install them normally.

We couldn’t measure the power consumption of the Nvidia GeForce 7950 GX2 card because it doesn’t work on uncertified mainboards (for details read our review called Two for One: Nvidia's Dual-Chip GeForce 7950 GX2 Reviewed ). So, we can only say that Nvidia reports a peak consumption of 143W for this device. By our own estimate, the GeForce 7950 GX2 works at frequencies similar to the GeForce 7900 GT (which consumes 48W) and can hardly require more than 110-120W.

Power Consumption Details (Click to enlarge):

There are no surprises in the power consumption diagrams: incorporating less transistors and having a micro-architecture optimized for low power consumption, the Nvidia GeForce 7900 GTX eats 33% less of power than its opponent under maximum 3D load.

When idle or under high 2D load, both the top-end graphics cards from ATI and Nvidia need almost the same amount of power.

Under the peak load, the Radeon X1900 XTX sucks in a lot of juice from its additional power connector and consumes the same 45W as the GeForce 7900 GTX from the mainboard’s power circuitry.

Noise Level

The decibel is a logarithmic rather than linear measurement unit, so an increase in the sound level by 3dB corresponds to a twofold increase in the sound intensity. However, because of the non-linearity of human hearing it is assumed that the perception of a sound source having become two times louder corresponds to a sound level increase by 10dB.

The diagrams show that the coolers of these graphics cards produce noise with an intensity of about 45dBA in 2D mode, and the GeForce 7950 GX2 is even a little quieter than the other two products. But as soon as you launch a 3D game, the Radeon X1900 XTX and the GeForce 7950 GX2 speed up their fans and worsen your acoustic comfort (the latter sounds somewhat better, though). The fan of the GeForce 7900 GTX remains tranquil in almost any case, thus making this product the most comfortable to use of the three.

High-End Graphics Cards

The high-end graphics card class currently includes a multitude of diverse products that vary in their actual price from $250 to $350 and even to $400 depending on the manufacturer and accessories. And a more expensive product is not necessarily faster or better suited for the next generation of games than a cheaper one. Graphics cards of this category deliver similar performance, making your shopping choice harder.

The Radeon X1900 XT and the Radeon X1900 GT stand out among the more expensive products. These two are meant for top-end computer systems and come with a dual-slot cooler whereas the Radeon X1900 GT and the GeForce 7900 GT have smaller coolers. Unlike most of ATI’s Radeon X1900 and X1800 cards, GeForce 7900 GT cards don’t generally support the video capture feature, but this is not a big problem in the era of digital cameras. All the mentioned graphics card models support dual-link DVI.

Power Consumption

Power Consumption Details (Click to enlarge):

A very economical solution, the Nvidia GeForce 7900 GT requires much less power than ATI’s Radeons it rivals with. For example, the Radeon X1900 XT, which corresponds to the GeForce 7900 GTX in performance, consumes more than twice the amount of power the 7900 GT needs. Although the Radeon X1900 GT is an economical solution too, it looks voracious in comparison with the GeForce 7900 GT.

Noise Level

We’ve already said it in our reviews that Nvidia took a very ill-designed cooling system for its GeForce 7900 GT. As a result, it is the loudest product among top-end graphics cards because it cannot vary its fan speed depending on the GPU temperature and is always audible when your computer is turned on.

The Radeon X1900 XT and the Radeon X1800 XT come with identical cooling systems and produce the same amount of noise (45dBA), which is a little over the noise level of the Radeon X1900 GT. You should be aware that there exist versions of the Radeon X1900 GT, Radeon X1800 XL and Radeon X1800 GTO with different cooling systems and, accordingly, with different noise characteristics.

Performance-Mainstream Graphics Cards

The arrival of the GeForce 7600 and 7900 cards made ATI reconsider its product line-up and release the Radeon X1900 GT and Radeon X1800 GTO based on the company’s high-end graphics processors. As a result, ATI’s opponent to the GeForce 7600 GT is a rather massive device with relatively high power consumption and appropriate chassis and power requirements.

The GeForce 7600 GT and the Radeon X1800 GTO/X1800 XL support dual-link DVI outputs (only one such output is available on the GeForce 7600 GT), so you can use your large monitor with any of them.

Power Consumption

Power Consumption Details (Click to enlarge):

Nvidia’s solution consists of only 177 million transistors whereas the Radeon X1800 GTO incorporates as many as 320 million, even though some of them are disabled. So, the results look quite logical. You should realize that a power consumption of 50W is not high nowadays, so the biggest problem with the Radeon X1800 GTO is its large dimensions due to the use of a 256-bit memory bus (but this same bus ensures high performance when full-screen antialiasing is enabled).

Noise Level

As opposed to the GeForce 7900 GT, the 7600 GT model has a fan that can change its speed depending on the GPU temperature, so the latter card is more comfortable to use.

However, the fan speed increases as soon as the GeForce 7600 GT chip reaches a certain temperature, and the noise level becomes higher than that of any opponent or even of the GeForce 7900 GT.

The cooling systems of the Radeon X1800 XL, Radeon X1800 GTO and Radeon X1900 GT are interchangeable and exist in two varieties:

It is possible that even different batches of the same card from the same manufacturer will come with different coolers, so you may want to make sure which cooler the card is equipped with before the purchase. You can replace the cooler by yourself, too.

Mainstream Graphics Cards

The price range of $99-199 has become a very lucrative sector of the market, showing some quick growth in the last years, according to Nvidia’s estimates. Considering that such products are relatively easy to manufacture, there is currently available a great multitude of various models on such graphics processors as Radeon X1600 XT, Radeon X1600 Pro, GeForce 7600 GS and GeForce 6600 GT (for details see our article called Knowing the Depths: NVIDIA GeForce 6600 GT Architecture). Each such product may differ from others in its physical characteristics like the sound level of its cooler. You should keep this fact in mind when analyzing the numbers published below which refer only to the GPU developers’ reference designs.

Note also that the GeForce 6600 GT, although on the same level with the other products, does not support dual-link DVI which is necessary for large monitors. So, if you buy a graphics card to work in resolutions of 1920x1200 and higher, you may want to consider GeForce 7 or Radeon X1000 series products.

Power Consumption

We had to down-clock a GeForce 7600 GT to emulate the GeForce 7600 GS, so the real GeForce 7600 GS may have slightly lower power consumption than shown.

Power Consumption Details (Click to enlarge):

Manufactured on 110nm tech process, the GeForce 6600 GT consumes 47 watts, which is in fact the power consumption of the Radeon X1800 GTO. Thus, it is the most power-hungry device in the mainstream category. The 90nm GeForce 7600 GS boasts the lowest power draw at 27W. The Radeon X1600 cards need the same amount of power, a little more than their opponent requires. Although the Radeon X1600 Pro has lower frequencies than the Radeon X1600 XT, it uses power-hungry GDDR2 memory and works at the same voltage, so as a result it requires as much power as the senior model in the series.

Noise Level

A vast majority of GeForce 7600 GS cards available on the market are equipped with a passive cooling system, so this card should be considered the quietest among the tested ones. As for the non-qualification Radeon X1600 XT sample from ATI, it is the noisiest graphics card of all in this batch, because its cooling system always works at its maximum speed. As we see by Sapphire Radeon X1600 Pro, the cooling solutions used on graphics cards of the kind are usually quiet: although the mainboards can manage the fan rotation speed in the VGA cooling systems, this feature is never really used. As a result, the solutions of this type can be considered very quiet, especially since most graphics card vendors equip their Radeon 1600 Pro/XT with passive cooling systems.

Entry-Level Graphics Cards

The same as with the mainstream category, entry-level products are made by the own design of the graphics card maker who tries to reduce the manufacturing cost and meet the requirements of the clients who often provides a list of desired features. So, the physical parameters of such products may vary in a very wide range.

To test the Radeon X1300 Pro and S3 Graphics Chrome S27 we used the solutions from ATI and S3, while for Nvidia GeForce 7300 GS we picked a product from Gigabyte equipped with a passive cooling system. Note that neither GeForce 7300 GS, nor Chrome S27 support dual-link DVI on the chip level.

Power Consumption

Power Consumption Details (Click to enlarge):

We used to be impressed with the 23W of power consumed by S3 Graphics Chrome S27. However, to day we can pronounce the new economical king: Nvidia GeForce 7300 GS. Despite the low performance and only 64-bit memory bus, this solution eats up less power than any of the graphics cards we have tested today.

Noise Level

Of course, the GeForce 7300 GS graphics card with the passive cooling cannot generate any noises. We decided not to measure the noise level of the ATI Radeon X1300 Pro non-qualification sample, because it will be the same as that of the Radeon X1600 Pro. However, most of the currently selling graphics cards of the kind are usually equipped with passive cooling systems. As for the Chrome S27, we can only mention the level of generated noise for this particular reference graphics card. It equals 45dBA, which hardly illustrates anything, because there are no products in the market at this time.

Conclusion

Power Consumption

In the six months that have passed since out last study of power consumption of graphics cards Nvidia has released a series of products that have established it as the manufacturer of the most power-economical desktop GPUs as well as the provider of GPUs with the most appealing performance-per-watt ratio (if you put aside the quad-SLI system :)).

If you compare competing graphics cards on ATI’s Radeon and Nvidia’s GeForce GPUs, you will nearly always find that the latter consume less power than the former. If you are looking for the most economical graphics card with all modern features supported, then the GeForce 7300 GS consuming only 16W of power is a remarkable solution.

The power consumption factor is most important when it comes to top-end expensive products because an upgrade to the level of GeForce 7900 or Radeon X1800/X1900 may call for the purchase of a new power supply, making you spend even more money. With typical mainstream and entry-level graphics cards it doesn’t matter much that this card consumes a little more than that one: they all have a very modest power draw, and a good 250-300W power supply will suffice to use any of them.

Silence-oriented systems, like Home Theater Personal Computers (HTPCs) make an exception. Another exception is poorly balanced systems from computer manufacturers who install power-hungry dual-core CPUs into small system cases and have to pick up the rest of the components with as low power consumption as possible.

Noise Level

While it’s all clear with power consumption, Nvidia’s cooling systems call for improvement in more cases than one.

If you value silence, the GeForce 7900 GTX is the most appealing choice. It is very quiet and remains such nearly always. The Radeon X1800/X1900 cards and the GeForce 7950 GX2 are less appealing in this respect as they speed up their blowers to high speeds in 3D mode. However, since no hardcore gamer has his system running full-power 24/7, and uses it for 2-3 hours a day only, then the noise level may not be the top priority criterion.

The GeForce 7900 GT with a cooler of Nvidia’s design is the least comfortable to use graphics card today. Although its power draw is considerably lower than that of the Radeon X1900 GT, the latter is much quieter, especially when working in Windows 2D applications.

The standard fan of the GeForce 7600 GT is louder than the fan of its main opponent Radeon X1800 GTO.

As for the mainstream and value graphics accelerators, it all depends on the manufacturer’s desire to equip his product with a passive cooling solution, or to save some money by installing something louder and cheaper. Therefore, we would refrain from making any conclusions in this case.