by Ilya Gavrichenkov
04/30/2010 | 04:59 PM
AMD used to make it very obvious that it had no interest in the market of miniature and low-power computers with limited performance, i.e. netbooks and nettops. Of course, this has not prevented some makers from offering such computers built with AMD components. For example, a compact desktop machine called Zino HD from Dell. However, this trend hasn’t yet become mainstream, and most nettops out there are still based on Intel and Nvidia hardware. Moreover, there are almost no AMD parts in the market that would allow any user to build a mini-ITX nettop on their own.
It isn’t AMD cannot produce CPUs with low heat dissipation that could be used as a basis for computers like that? On the contrary, AMD offers Socket AM3 processors for desktop PCs with a thermal design power of 45, 25 and even 20 watts. In our opinion, CPUs like that could become popular among people who would like to assemble a nettop with their own hands as they offer good performance, especially in comparison with Intel Atom, and are just as good as Intel’s modern LGA775 Celeron series in terms of heat dissipation. It looks like AMD’s power-efficient CPUs for desktop PCs are a good offer that fits perfectly into the free market segment between Intel Atom and Intel Celeron series.
It is a different story with the mainboards. AMD’s belief that their CPUs are no good for compact multimedia PCs has led to the fact that there are nearly no modern Socket AM3 mainboards in the mini-ITX form-factor in the today’s market. It is a shame considering that AMD’s new integrated chipsets such as the AMD 785G and 880G would be optimal for nettops as they feature a rather fast graphics core capable of hardware HD video acceleration, support all modern interfaces, and have modest heat dissipation. So, the only obstacle that a developer of compact Socket AM3 mainboards has to face is the rather large physical size of the CPU socket which should also have a rather large cooler retention mechanism around it. Besides, each chipset from AMD consists of two chips, making designing small PCBs even more complicated.
Fortunately, some developers do not find those difficulties insurmountable. Sapphire’s recent release of a mini-ITX mainboard for the new generation of energy-efficient Socket AM3 processors has become a good stimulus for writing this review. We are going to talk about energy-efficient AMD processors in terms of their suitability for compact and economical computers for home and office.
If we were to rank AMD processors according to their heat dissipation, we’d be able to single out six classes. The majority of desktop processors from AMD have a TDP of 95, 80 or 65 watts, depending on the number of cores. Some enthusiast-targeted models may even get as high as 125 and 140 watts. As opposed to that, the energy-efficient models have a heat dissipation of 45 or 25 watts. The dual-core Athlon II X2 250u belongs to the latter category as its TDP is 25 watts. The letter “u” in the model name obviously comes from “ultra energy efficient”. AMD’s ordinary energy-efficient processors with a TDP of 45 watts are marked with the letter “e”.
The 25 W dual-core Athlon II series currently includes only two models. Besides the Athlon II X2 250u, there is a faster modification - Athlon II X2 260u. Both are produced in exactly the same way, however. These ultra-economical CPUs are simply downclocked (the opposite of overclocked). As you know from our article called CPU Overclocking vs. POwer Consumption, it is the CPU voltage that affects the heat dissipation and power consumption of an overclocked processor the most. Increasing it leads to a considerable increase in the CPU thermal and electrical parameters. The opposite is true, too: if you reduce the voltage, you will make the CPU consume less power and dissipate less heat. Therefore, it is no wonder that AMD’s energy-efficient processors have a reduced voltage. For example, the ordinary Athlon II X2 with a TDP of 65 watts has a default voltage up to 1.425 volts whereas its 25 W cousin has a default voltage of 1.15 volts or less.
The downside of the reduced voltage is that such a CPU has to be clocked at a lower frequency and proves to be considerably slower than its full-voltage counterparts. For example, the Athlon II X2 250u has a clock rate of only 1.6 GHz, which is much lower than the clock rate of the ordinary Athlon II 250.
On the other hand, the Athlon II X2 250u remains a full-featured member of the Regor family. It is based on a 45 nm die, has two computational cores (each with a dedicated 1 MB L2 cache), and is compatible with the Socket AM2/AM3 infrastructure, supporting both DDR2 and DDR3 SDRAM.
Of course, there is no use in comparing the performance of an energy-efficient processor with an ordinary one that has a clock rate higher than 3 GHz. The result is obvious beforehand. The difference in power consumption is obvious, too. Working at a clock rate of 1.6 GHz with a voltage of 1.06 V, our CPU had very low power consumption – no higher than 18 watts – under full load.
The results of a temperature test were downright funny. Using a Scythe Shuriken cooler, we tried to fry our Athlon II X2 250u up with the LinX 0.6.3 utility but the CPU did not get any hotter than 30 °C.
Even more amazingly, this CPU could run LinX for an hour after we had removed the fan from the Scythe Shuriken cooler. The max temperature was 66 °C with passive cooling like that (on an open testbed).
So, AMD has managed to produce a very economical processor that is eligible for a job in any energy-efficient and compact system. And if the system case is properly ventilated, this CPU can even work with a passive cooler!
Compact Socket AM3 mainboards were something improbable up till now. We just did not know about any solutions like that. There were Socket AM2 mini-ITX mainboards only, but in very limited quantities, too. Now it looks like the situation is going to change as Sapphire, one of AMD’s key manufacturing partners, has gotten into producing small mainboards for desktop Athlon II and Phenom II processors.
Although a mini-ITX mainboard with Socket AM3 is going to be a clear winner, Sapphire does not categorize it as a solution for home users. The company regards it as an industrial mainboard. Fortunately, this positioning does not imply any compromises in terms of design or specs, so the Sapphire IPC-AM3DD785G is just perfect for nettops and small HTPCs. We are not sure about its availability, but hope that everyone who likes it will be able to get it.
One glance at a photo of the mainboard is enough to realize how much effort has been invested into it by the developer. It certainly was not easy to fit all the necessary components onto the PCB as its central part is occupied by the CPU socket and cooler retention mechanism. Sapphire team has coped with the task well, however. They even put a full-featured 4-channel CPU voltage regulator for CPUs with up to 125W TDP. So, notwithstanding its compact size of 170x170 millimeters, IPC-AM3DD785G does not impose any limitations on your CPU choice. It is compatible with all modern Athlon II and Phenom II series processors.
Featuring Socket AM3, the mainboard also has two slots for DDR3 SDRAM modules. These slots are placed very close to the CPU socket, so you may have some problems with certain coolers. For example, our Scythe Shuriken barely fits onto the IPC-AM3DD785G, its heat pipes pressing against the DIMMs. Many high-performance coolers of the tower design, like the Thermalright Ultra-120 eXtreme, will not be compatible with this mainboard at all.
The miniature mainboard from Sapphire is based on the AMD 785G chipset and features integrated Radeon HD 4200 graphics core.
This core is DirectX 10.1 compatible and offers good performance (for an integrated GPU). It also supports hardware decoding of HD video in popular formats, allowing to use AMD 785G in multimedia centers with rather slow CPUs. Moreover, if you are not entirely satisfied with the functionality and potential of Radeon HD 4200, the IPC-AM3DD785G offers a PCIe x16 slot for an external graphics card.
AMD 785G is paired with an AMD SB710 South Bridge here. Although it is a junior chip among AMD’s South Bridges, the SB710 is sufficiently functional for a mini-ITX mainboard. Thanks to it, Sapphire IPC-AM3DD785G can offer four SATA-300 ports, one PATA-133 port for storage devices, and ten USB 2.0 ports, six of which are laid out on the mainboard back panel. Also there are three analog audio-jacks (provided by a six-channel VIA VT1708S codec) and an RJ-45 connector (supported by a Gigabit Ethernet controller from Atheros).
Monitors can be connected to the mainboard’s analog D-Sub or digital HDMI port. There is no DVI but an HDMI-DVI adapter is included into the box. There is no digital SPDIF output at the back panel, either. It is offered as an onboard pin-connector only.
The North and South Bridges are placed close to each other on the PCB and share a single heatsink that covers them both. The heatsink is rather small and gets very hot at work. The user manual recommends you to pay attention to it and make sure your system case is ventilated properly. Sapphire even includes an additional 40mm fan into the box as a kind of a hint.
Summing everything up, the design of Sapphire IPC-AM3DD785G leaves a highly positive impression. There are no problems in its BIOS Setup, either. The only issue we can find with it is the scarcity of settings. The BIOS only offers such basic options as turning the integrated controllers on/off, choosing the boot device order, or setting up the system date and time. There are no options for overclocking or downclocking the CPU or graphics core. You cannot change the clock rates or voltages of the components. There are even no options to set the frequency and timings for system memory.
On the other hand, the BIOS supports Q-Fan technology for the mainboard to control the speed of the CPU cooler fan. You can specify the key parameters of that technology manually.
Winding up the description of the mini-ITX mainboard from Sapphire, we would like to show you its full specifications list:
We described Athlon II X2 250u processor with 25 W TDP as an intermediate solution filling in the gap between energy-efficient low-performance Intel Atom and relatively fast, but much “hotter” Intel Celeron processors. Intel has no solutions to offering this pretty large market segment that is why ultra-economical AMD CPUs have every chance of taking it over. This would be the prospective for our upcoming test session of the Athlon II X2 250u platform.
Keeping in mind that Sapphire IPC-AM3DD785G mainboard we are going to use is based on AMD 785G chipset with pretty decent 3D performance and broad multimedia functionality, we decided to also include a few alternative mini-ITX platforms based on integrated Nvidia chipsets. We are going to test Intel Atom processor as part of NVIDIA ION platform, and Intel Celeron was installed into Zotac 9300-ITX WiFi mainboard on GeForce 9300 chipset.
Since Athlon II X2 250u is a dual-core processor, we chose dual-core Celeron and Atom modifications for our today’s tests. As a result, the complete list of hardware and software components for our test session included the following:
We used integrated graphics cores of the mainboard chipsets in all tests.
We would like to offer you formal specifications of participating energy-efficient dual-core processors side by side, as it will help you to better interpret the obtained results:
SYSmark 2007 confirms our assumptions that Athlon II X2 250u can be positioned in between the Atom and Celeron series in terms of performance. This CPU proves to be about twice as fast as the dual-core Atom but inferior to the dual-core Celeron E3400. In some applications, for example during video content processing, AMD’s energy-efficient processor even outpaces the Celeron which consumes more power and has a 60% higher clock rate.
We measure the speed of Adobe Flash technology by benchmarking the performance in a 3D arcade called Tanki Online which client is written in Flash.
We also measured the number of frames per second when playing HD video with a Flash player from Youtube.com. Note that we use Adobe Flash Player 10.0.45.2 which cannot utilize the hardware capabilities of graphics accelerators.
The results suggest that the AMD-based system is slower than the Celeron-based one in Web applications, especially those written in Flash. However, you should keep it in mind that Celeron is not an energy-efficient solution, so it is quite natural for Athlon II X2 250u to be inferior to it in sheer performance. Moreover, Athlon is much faster than Intel’s energy-efficient Atom clocked at a similar frequency.
The ultra-economical Athlon II and AMD 785G-based mini-ITX mainboard deliver higher performance than the ION platform in typical home applications. Moreover, running an audio/video encoding or image processing application on the ION will be a test of your patience whereas Athlon II X2 250u copes with it within a reasonable amount of time. Of course, the Celeron-based system is even faster, but it is a traditional PC rather than a power-efficient one.
By the way, the Celeron-based computer is not always faster when it comes to video transcoding. There are applications that can utilize GPU’s resources along with those of the CPU for this job. Cyberlink MediaShow Esspresso 5.5 is an example.
This program can put shader processors of the integrated graphics core in AMD platform to good use and runs faster than on the platforms with Intel CPUs and Nvidia integrated graphics.
Today’s multimedia players can utilize GPU resources, too. Every modern graphics core incorporates a hardware engine for video decoding. As a result, the CPU does not have much work to do during HD video payback in popular formats.
The diagram shows the CPU load during HD video playback in H.264 format (30 Mbps) with Media Player Classic Home Cinema. As you can see, it is no higher than 25%, which is a very good result. Interestingly, the results of the Celeron E3400 and Athlon II X2 250u are almost identical whereas the ION platform shows lower CPU utilization. This is not because of some exclusive technology from Nvidia, however. From the OS’s point of view, the CPU with Hyper-Threading technology has twice the number of cores and its result under low load is understated.
As we are benchmarking not just CPUs but compact integrated platforms, we should take a look at their graphics performance as well. The systems with Intel CPUs feature Nvidia GeForce 9300 graphics whereas the Athlon II X2 250u works with a mainboard which is based on AMD 785G chipset with an integrated Radeon HD 4200 graphics core. The difference in graphics cores may have a profound effect on the performance of these platforms in 3D applications.
As you can see, AMD platform still cannot match Celeron E3400-based one. GeForce 9300 seems to deliver higher 3D performance than Radeon HD 4200, by the way. This is the only explanation of why ION is occasionally faster than Athlon II X2 250u-based platform.
Thus, the mini-ITX platform based on AMD components, including an ultra energy efficient processor, proves to be substantially faster than Nvidia ION, but cannot match the mini-ITX platform with a full-featured desktop Celeron. This should not be viewed as a failure of the Athlon II X2 250u because modern compact systems are not supposed to be extremely fast. They must be power-efficient in the first place. Their users are interested in having an optimal ratio of performance to power consumption, rather than in each of these too parameters individually.
From a theoretical point of view, the key components of our configurations have the following peak power consumption.
But we know that theoretical data do not always agree with what the practical experiments show. Therefore, we performed some power consumption tests where we measured total system power consumption of our platforms (without the monitor). All the readings were taken “past” the power supply unit and represent overall power consumption of all system components. In this case we do not take into account the efficiency of the PSU itself. During our tests we used 64-bit LinX 0.6.4 utility to load the CPUs to the utmost extent. We used FurMark 1.8.0 to load the graphics sub-system. All available power-saving technologies were activated.
Nvidia ION is about 30% more economical in idle mode than its opponents that showed similar results. In other words, the energy-efficient Athlon II X2 250u cannot boast any specific achievements in terms of power consumption in idle mode.
When there is some work for the CPU to do, the situation changes dramatically. Our platform based on a dual-core Celeron begins to consume far more than the AMD platform which fits in between the Atom and Celeron in terms of power draw.
Under high graphics load the AMD 785G-based platform needs about as much power as Nvidia ION based one. It means that despite Nvidia’s claims, GeForce 9300 can hardly be considered an energy-efficient solution.
The AMD platform takes an in-between position under mixed load, too. This position corresponds to its level of performance, actually.
Power consumption during video playback is the only test where Athlon II X2 250u platform is worse than its opponents. This process is accelerated by the integrated graphics core and GeForce 9300 is obviously more efficient than Radeon HD 4200 at this task. Besides, Celeron-based platform keeps the CPU in a power-saving state during this test whereas Athlon II X2 250u is working at its full clock rate.
The article turned out fairly short, but quite extensive. We managed to introduce to you several very interesting hardware pieces that will undoubtedly attract many users’ attention.
First, it was AMD Athlon II X2 250u processor that presents an excellent example of effective downclocking. Without making any changes to the existing processor microarchitecture, AMD managed to create a pretty energy-efficient but also quite fast processor that fit perfectly into the niche between Intel Atom and Intel Celeron. By lowering the core voltage and nominal clock frequency of the Regor core, AMD made Athlon II X2 250u an excellent choice for quiet and compact systems, because this CPU consumes no more than 18 W of power (according to our tests), but performs much faster than Intel Atom. In other words, Athlon II X2 250u is a great product for universal nettops that will be way ahead of Intel Atom based ones in pure performance.
Second, we were extremely pleased with Sapphire IPC-AM3DD785G mainboard. We used to complain about the absence of miniature mainboards for AMD processors. So, finally, a long-awaited solution is here. Sapphire offered an excellent multimedia Socket AM3 board, which will definitely find its way into nettops, HTPC and compact systems. Sapphire IPC-AM3DD785G mainboard is based on AMD 785G chipset and not only features a high-performance Radeon HD 4200 graphics core, but also provides a range of expansion options including even an external graphics card slot.
And most importantly, Athlon II X2 250u processor and Sapphire IPC-AM3DD785G mainboard are a ready-to-go energy-efficient, fast and functional platform that may become a superb alternative to mini-ITX solutions with Intel processors and Nvidia chipsets. A platform like that has every chance of becoming a faster alternative to a pretty popular Nvidia ION, because a computer built around it will be a fully-functional home system rather than just a hardware media player.
However, the platform we discussed today may face two serious obstacles. They are the price and availability. At this time you will hardly be able to buy AMD Athlon II X2 250u or Sapphire IPC-AM3DD785G anywhere in retail. And so far we have no idea if things are going to change any time soon, and if AMD would be really interested in these changes. It could be that AMD is planning to start mass invasion into the market of nettops and other miniature systems like that only in early 2011, when their Llano and Bobcat processors come out, and the today’s Athlon II X2 250u is merely a product designed specifically for some close partners.