Power
A card's GPU, clock speeds, and overall design determine the kind of power draw it creates on your system. Moving parts on the heat sink sometimes require more power to run, which is what might give silent cards a slight advantage in this area. However, just because there are no moving parts on a card doesn't mean that it won't still draw large amounts of power. Only one of our cards required an external power connection from the power supply; the rest simply drew their power from the PCIe slot. The ASUS EN7800 GT Top Silent, our most powerful card, required a 6-pin PCI Express power connector, and it's no surprise that we saw the highest power draw from this card.
We tested power by measuring the total wattage of the system with each card installed in two different states. The first state is while the system is idle, without any programs running, and the second state is under load, by running a graphically intensive benchmark. The benchmark we used to stress the graphics cards was 3DMark06, specifically, the fill rate (single and multi-texturing) and the pixel shader tests.
We see initially how while idle, the system draws less power than what you might expect to see for some of these graphics cards. The highest idle power level we see is 135 watts for the Asus 1600 XT and 7800 GT, as well as the Gigabyte 7300 GT and X1300 Pro. The ASUS 7600 GS 512 gets the lowest idle power wattage, which is somewhat interesting as it certainly isn't the least powerful card. With a total difference in idle power of only 10W, though, most of the cards are doing a good job under idle conditions. Let's see what happens when we actually put the cards to work.
As expected, the ASUS 7800 GT gives the system a significantly higher power draw under load, followed by the Gigabyte 7600 GT, the second most powerful card. The fact that these two cards are the most power-hungry makes sense, as does the fact that the ASUS 6600 GT gets a similarly high load wattage, since this is an older, less efficient part. The Gigabyte X1300 draws the least amount of power under load; this isn't surprising given its low performance, though the Sparkle 7300 GS Ultra 2 is somewhat more power-hungry in spite of the fact that it performs about the same. The Gigabyte 7300 GS, another low-performance card, gets an even higher wattage due to its faster memory.
Aside from the few highest performance cards, all of these cards get very similar results in terms of power draw. This similarity and consistency in power draw among all of these cards seems to say something about the design of silent cards in general. While it is technically possible to cool more power hungry GPUs with a fanless solution, most manufacturers are targeting lower heat GPUs for their silent cards, as the cooling solutions do not need to be as extravagant (or costly).
Heat
As we touched on in the introduction, controlling heat levels is essential to the smooth operation of a graphics card. Because there are no moving parts in any of these cards, their heat sinks must be designed to provide adequate heat dissipation over long time periods, as most people don't sit down to play games for only a few minutes at a time. Whether or not these silent cards run cool or hot will depend not only on the card, but on things like your case ventilation and environment in general. Also, heat levels may vary even among different parts of the same model, but we can get a general idea of the heat that will be generated by these different cards while idle and under stress.
Similar to the way we tested power consumption, we measured the heat level of the card in two different states: idle and after five minutes of stress testing. In order to stress test the card, we would traditionally measure heat levels after a few looped game benchmarks but for this review, we made use of ATI Tool's "Scan for Artifacts" function on their "fuzzy cube" 3D view. This came in very handy for us, because it stresses both ATI and NVIDIA cards by basically drawing a 3D cube with some kind of fuzz map over and over. We found that about five minutes of "scanning" with this tool gave us the same level of stress as running our usual number of Splinter Cell: Chaos Theory benchmark loops, only it was much easier to accomplish the stress testing.
Unfortunately, we weren't able to include any ATI cards in our heat tests, because apparently none of these cards have on-die temperature sensors to give us heat level readings. We were able to use NVIDIA's built-in heat meter in the driver to get readings from the NVIDIA cards, however, so we will look at these numbers for now.
Something we see right away is that the EVGA 7600 GS has a much lower idle temperature than the other cards. The Albatron 7300 GT gets a fairly low temperature while idle, and interestingly the tiny Sparkle 7300 GS Ultra 2 gets the highest idle temperature of the group.
Unsurprisingly, the ASUS 7800 GT gets a dramatically higher temperature than the rest of the cards while under load -- high enough to perhaps warrant some concern. Generally, a core temperature this high is bad news, but it would seem the ASUS EN7800 GT Top Silent was designed to be able to handle temperatures this high. This might be an issue however for someone with poor case ventilation or those who live in a very hot climate without conventional cooling in their building.
The two coolest operating cards under load are the same ones that were the coolest while idle: the Albatron 7300 GT and EVGA 7600 GS, with the Albatron card running slightly cooler. Again we see that the Sparkle 7300 GS Ultra 2 generates quite a bit of heat considering its small size and low performance, though the small size is the likely culprit. The high heat and power load for this card are both negatives, and since it performs very poorly in most of the games the only plus the Sparkle 7300 GS Ultra 2 has going for it is it's small size. It will fit in just about any computer case, no matter how small or crowded it is. This isn't saying much for the card however, and unless you can find it for a ridiculously low price we don't recommend buying one.
A card's GPU, clock speeds, and overall design determine the kind of power draw it creates on your system. Moving parts on the heat sink sometimes require more power to run, which is what might give silent cards a slight advantage in this area. However, just because there are no moving parts on a card doesn't mean that it won't still draw large amounts of power. Only one of our cards required an external power connection from the power supply; the rest simply drew their power from the PCIe slot. The ASUS EN7800 GT Top Silent, our most powerful card, required a 6-pin PCI Express power connector, and it's no surprise that we saw the highest power draw from this card.
We tested power by measuring the total wattage of the system with each card installed in two different states. The first state is while the system is idle, without any programs running, and the second state is under load, by running a graphically intensive benchmark. The benchmark we used to stress the graphics cards was 3DMark06, specifically, the fill rate (single and multi-texturing) and the pixel shader tests.
We see initially how while idle, the system draws less power than what you might expect to see for some of these graphics cards. The highest idle power level we see is 135 watts for the Asus 1600 XT and 7800 GT, as well as the Gigabyte 7300 GT and X1300 Pro. The ASUS 7600 GS 512 gets the lowest idle power wattage, which is somewhat interesting as it certainly isn't the least powerful card. With a total difference in idle power of only 10W, though, most of the cards are doing a good job under idle conditions. Let's see what happens when we actually put the cards to work.
As expected, the ASUS 7800 GT gives the system a significantly higher power draw under load, followed by the Gigabyte 7600 GT, the second most powerful card. The fact that these two cards are the most power-hungry makes sense, as does the fact that the ASUS 6600 GT gets a similarly high load wattage, since this is an older, less efficient part. The Gigabyte X1300 draws the least amount of power under load; this isn't surprising given its low performance, though the Sparkle 7300 GS Ultra 2 is somewhat more power-hungry in spite of the fact that it performs about the same. The Gigabyte 7300 GS, another low-performance card, gets an even higher wattage due to its faster memory.
Aside from the few highest performance cards, all of these cards get very similar results in terms of power draw. This similarity and consistency in power draw among all of these cards seems to say something about the design of silent cards in general. While it is technically possible to cool more power hungry GPUs with a fanless solution, most manufacturers are targeting lower heat GPUs for their silent cards, as the cooling solutions do not need to be as extravagant (or costly).
Heat
As we touched on in the introduction, controlling heat levels is essential to the smooth operation of a graphics card. Because there are no moving parts in any of these cards, their heat sinks must be designed to provide adequate heat dissipation over long time periods, as most people don't sit down to play games for only a few minutes at a time. Whether or not these silent cards run cool or hot will depend not only on the card, but on things like your case ventilation and environment in general. Also, heat levels may vary even among different parts of the same model, but we can get a general idea of the heat that will be generated by these different cards while idle and under stress.
Similar to the way we tested power consumption, we measured the heat level of the card in two different states: idle and after five minutes of stress testing. In order to stress test the card, we would traditionally measure heat levels after a few looped game benchmarks but for this review, we made use of ATI Tool's "Scan for Artifacts" function on their "fuzzy cube" 3D view. This came in very handy for us, because it stresses both ATI and NVIDIA cards by basically drawing a 3D cube with some kind of fuzz map over and over. We found that about five minutes of "scanning" with this tool gave us the same level of stress as running our usual number of Splinter Cell: Chaos Theory benchmark loops, only it was much easier to accomplish the stress testing.
Unfortunately, we weren't able to include any ATI cards in our heat tests, because apparently none of these cards have on-die temperature sensors to give us heat level readings. We were able to use NVIDIA's built-in heat meter in the driver to get readings from the NVIDIA cards, however, so we will look at these numbers for now.
Something we see right away is that the EVGA 7600 GS has a much lower idle temperature than the other cards. The Albatron 7300 GT gets a fairly low temperature while idle, and interestingly the tiny Sparkle 7300 GS Ultra 2 gets the highest idle temperature of the group.
Unsurprisingly, the ASUS 7800 GT gets a dramatically higher temperature than the rest of the cards while under load -- high enough to perhaps warrant some concern. Generally, a core temperature this high is bad news, but it would seem the ASUS EN7800 GT Top Silent was designed to be able to handle temperatures this high. This might be an issue however for someone with poor case ventilation or those who live in a very hot climate without conventional cooling in their building.
The two coolest operating cards under load are the same ones that were the coolest while idle: the Albatron 7300 GT and EVGA 7600 GS, with the Albatron card running slightly cooler. Again we see that the Sparkle 7300 GS Ultra 2 generates quite a bit of heat considering its small size and low performance, though the small size is the likely culprit. The high heat and power load for this card are both negatives, and since it performs very poorly in most of the games the only plus the Sparkle 7300 GS Ultra 2 has going for it is it's small size. It will fit in just about any computer case, no matter how small or crowded it is. This isn't saying much for the card however, and unless you can find it for a ridiculously low price we don't recommend buying one.
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Josh Venning - Thursday, August 31, 2006 - link
I also forgot to mention that some people use their pcs in home theater systems as well. This would be another case when you want as little noise from your computer as possible.imaheadcase - Thursday, August 31, 2006 - link
That was not always the case, my 9700 Pro i still use when fan went out a year ago, works like a charm without it on. It was in its time the high end card, lets hope those days come buy again :Deckre - Thursday, August 31, 2006 - link
What a great review, when tom did their silent VC review, they included a grand total of three cards...pfft. nice job anand.I have the 7600GT, very sweet and 0dB is oh so nice.
Josh Venning - Thursday, August 31, 2006 - link
We just wanted to say thanks all for your comments and we are still trying to make sure we've caught any errors. (there are actually only 20 cards in the roundup and not 21) As Derek said, these cards were included in the article because we requested any and all silent cards that any of the manufacturers were willing to give us to review. That's also why we have more cards from ASUS and Gigabyte than the others.Olaf van der Spek - Thursday, August 31, 2006 - link
Because the videocard industry hasn't introduced such a bad design as the netburst architecture.
epsilonparadox - Thursday, August 31, 2006 - link
No they've introduced worse. When they recommend a second PS just for grafx or even a 1Kw single PS, they've taken intel's lack of thermal control to a whole new level.DerekWilson - Thursday, August 31, 2006 - link
graphics cards use much much less power in 2d mode than in 3d mode -- and even their 3d power saving capabilities are really good.this is especially true when you consider the ammount of processing power a GPU delivers compared to a CPU.
Theoretical peak performance of a current desktop CPU is in the 10-15 GFLOPS range at best. For a GPU, theoretical peak performance is at least one order of magnitude larger reaching up over 200 GFLOPS in high end cases.
I'm not saying we can reach these theoretical peak rates on either a CPU or a GPU, but a GPU is doing much much more work under load than a CPU possibly could.
Keep in mind we aren't even up to GHz on GPU cores. On the CPU front, Intel just shortened the pipeline and decreased clock speeds to save power -- doing more work in one cycle. This is absolutely what a GPU does.
And the icing on the cake is the sheer options on the silent GPU front. Neither AMD nor Intel make a fast desktop CPU that can be (easily) passively cooled. These parts are a testiment to the efficiency of the GPU.
On the flip side, ATI and NVIDIA push their high end parts way up in clock speed and power consumption trying as hard as possible to gain the performance crown.
There are plenty of reasons GPUs draw more power than a CPU under load, but a lack of thermal control or inefficient desing is not one of them. It's about die size, transistor count, and total ammount of work being done.
JarredWalton - Saturday, September 2, 2006 - link
I disagree with Derek, at least in some regards. The budget and midrange GPUs generally do a good job at throttling down power requirements in 2D mode. The high-end parts fail miserably in my experience. Sure, they consume a lot less power than they do in 3D mode, but all you have to do is look at the difference between using a Radeon Mobility X1400 and a GeForce Go 7800 in the Dell laptops to http://www.anandtech.com/mobile/showdoc.aspx?i=276...">see the difference in battery life.In 2D mode, graphics chips still consume a ton of power relatively speaking -- probably a lot of that going to the memory as well. A lot of this can be blamed on transistor counts and die size, but I certainly think that NVIDIA and ATI could reduce power more. The problem right now is that power use is a secondary consideration, and ATI and NVIDIA both need to have a paradigm shift similar to what Intel had with the Pentium M. If they could put a lot of resources into designing a fast but much less power-hungry GPU, I'm sure they could cut power draw quite a bit in both idle and load situations.
That's really the crux of the problem though: resources. Neither company has anywhere near the resources that AMD has, let alone the resources that Intel has. Process technology is at least a year behind Intel if not more, chip layouts are mostly computer generated as opposed to being tweaked manually (I think), and none of the companies have really started at square one trying to create a power efficient design; that always seems to be tacked on after-the-fact.
GPUs definitely do a lot of work, although GFLOPS is a terrible measure performance. The highly parallel nature of 3D rendering does allow you to scale performance very easily, but power requirements also scale almost linearly with performance when using the same architecture. It would be nice to see some balance between performance scaling and power requirements... I am gravely concerned about what Windows Vista is going to do for battery life on laptops, at least if you enable the Aero Glass interface. Faster switching to low-power states (for both memory and GPU) ought to be high on the list for next-generation GPUs.
DaveLessnau - Thursday, August 31, 2006 - link
I'm wondering why Anandtech tested Asus' EN7800 GT card instead of their EN7600 GT. That card would be more in line with Gigabyte's 7600 GT version and, I believe, is more available than the 7800 version. In the near future, I'd like to buy one of these silent 7600GTs and was hoping this review would help. Oh, well.DerekWilson - Thursday, August 31, 2006 - link
you can get a really good idea of how it would perform by looking at Gigabyte's card.as I mentioned elsewhere in the comments, we requested all the silent cards manufacturers could provide. if we don't have it, it is likely because they were unable to get us the card in time for inclusion in this review.