The Battle of Low-Power Processors: Best Choice for a Nettop

Thanks to Intel, nettops – small, inexpensive and power-efficient home systems – turned into the latest computer fashion. Today we are going to compare several processors that may become a basis for systems like that: Intel Atom 230, Intel Atom 330 and VIA Nano L2100.

by Ilya Gavrichenkov
09/24/2008 | 10:54 PM

When Intel announced their new Atom processor architecture this April, they predicted that there would appear new class of devices called network computers (netbooks and nettops) and spread widely real fast. We are already very well familiar with the first type of devices like that: ASUS Eee PC is a typical example of a netbook solution. These solutions and similar thin and light notebooks with little computational power but long battery life turned out very demanded and quickly became very popular. Nettops haven’t yet invaded the market so aggressively. Nevertheless, these small, power-efficient, inexpensive personal computers intended primarily for work with different Internet-services look very promising.

 

Although they started talking about nettops only now, this is not a principally new concept. For the last few years VIA have been developing low-power processors and miniature platforms. The results of their engineering efforts are currently available under EPIA brand name. These solutions are the actual forefathers of the new economical platforms formation.

However, the situation has become favorable for nettops acceptance only now. That is why Intel started popularizing this concept aggressively. Most users no longer have to leave their browser while working on their computer thanks to increasing popularity of social networks, Internet applications and on-line gaming. This user group is simply perfect for nettop concept. Especially, since these solutions usually feature very “homey” design making them look more like a consumer electronics device, are very small and have quiet cooling system, which makes them fit even for living-room environment.

There are currently several platforms in the market that can be used for nettop systems. Of course, they include Intel Atom processors, namely Diamondville type, and several solutions from VIA Technologies that have been working on power-efficient platforms like that for a few years now. Today we are going to compare all contemporary hardware configurations for nettop systems from theoretical and practical standpoints. Besides we will also learn if today’s special power-efficient processors can offer better combination of power consumption and performance than the already existing solutions.

Microarchitecture of Low-Power Processors

Intel Atom

Traditionally, Intel tries to use the same microarchitecture for different market segments. This helps lower the research and development expenses as well as production costs. There used to be only one exception to this rule: high-performance server processor on IA-64 microarchitecture aka Itanium. However, when Intel decided to once again expand their influence, they discovered that Core microarchitecture, just like its predecessors, was far not that universal and doesn’t fit for all occasions. For example, Core microarchitecture turned out not the best choice for ultra-portable computational devices, which require highly power-efficient components. And even though last generation Core 2 processors offer pretty good combination of performance and power consumption, their derivatives may not be widely used for small mobile devices.

This inspired Intel engineers to develop principally new x86 processors with Atom microarchitecture that would combine low power consumption, small size and low production cost. It is Atom processor family that Intel has been actively promoting for nettop systems. There is a special modification designed specifically for this market – Diamondville.

Speaking of Atom processors peculiarities, I would first of all like to point out that they have nothing in common with Core microarchitecture, not to mention NetBurst microarchitecture. That is why the common characterization methods based on the number of cores, clock frequency or the amount of cache-memory cannot be applied to them. Atom is kind of isolated from the rest of Intel products, the new microarchitecture cannot be directly compared with any of the ever existing solutions.

There is one fact that illustrates this statement very well. Atom is a CPU with in-order instructions execution, while all Intel processors starting with Pentium Pro launched in 1995 support out-of-order execution. Since Atom developers tried to maximize the performance-per-watt as much as possible, they had to “return to origins” like that. That is why in the new CPU they eliminated all architectural solutions that increase the power consumption more than performance. And even though it did in fact affect the performance of the final product, Intel doesn’t consider it a big problem: portable devices do not need as much computational power as regular notebooks and PCs based on traditional CPUs.

Atom’s pipeline has 16 stages, which is more than Core pipeline has. However, you shouldn’t draw analogies between Atom and NetBurst microarchitectures, because longer pipeline doesn’t always mean higher heat dissipation. In this case, the CPU needs a long pipeline in order to reach high working frequencies, at which a CPU with simplified microarchitecture will be able to perform at an acceptable level. And it is a pretty complicated task for Intel Atom, because this CPU can only execute two instructions at a time, while contemporary x86 processors can execute three or four instructions simultaneously.

However, sequential execution of instructions allows Atom microarchitecture not to decompose many x86 instructions into microops, like in CPUs with out-of-order execution. This way, Atom may actually execute simultaneously more than two instructions in Core’s terms. In other words, we can say that Atom has some sort of analogy to macro-fusion technology.

Nevertheless, Atom processors have two decoders, two integer execution units and two execution units for SSE and FP instructions. However, some integer operations such as multiplication and division are actually performed by the FP units, so they are not being processed fast enough. This way Atom is not the best choice for calculations, it was developed primarily for running the operating system, browser and similar simple tasks.

 

Taking into account the limited number of execution units and availability of only two decoders, using them efficiently is one of the main tasks for Atom developers to solve. Especially since sequential instructions execution may cause the pipeline to idle a lot while waiting for the requested data to arrive from the memory. Therefore, Atom has certain algorithms that allow partially avoid this problem. This microarchitecture has Safe Instructions Recognition mechanism that allows the processor to let those instructions that do not need to wait for any data to get ahead in the queue and be processed first. However, Atom’s main trump here is support of Hyper-Threading technology that came back from Pentium 4 processors. As a result, the operating system sees a single-core Atom processor as a dual-core CPU that can process two threads at a time. So, its execution units works a lot more effectively improving the performance greatly.

Atom 230 processors that are targeted for nettop systems work at 1.6GHz frequency and have a 512KB L2 cache. Their typical heat dissipation, however, is only 4W. I would like to remind you that the TDP of the today’s most power-efficient single-core mobile ULV Core 2 Solo processors is almost 40% higher: 5.5W. In other words, Atom does indeed lower the minimal TDP and power consumption levels for Intel x86 processors. And as for the performance, we are going to talk about it later today.

Atom processors are manufactured with today’s most advanced 45nm process. Atom’s die size is only 25sq.mm, which means that they are pretty inexpensive to make. Even the official Atom 230 price is set at $29, which is way lower than what any other contemporary ULV CPU would cost. This is all the results of simple and very energy-efficient microarchitecture. They reduced the number of processor functional units and as a result got a processor made of only 47 million transistors. So, no wonder that the results of this “optimization” are actually everywhere. Even L1 cache memory of Atom processors is a little smaller than that of other contemporary CPUs. It is only 56KB: 24KB for data and 32KB for instructions.

However, from the formal specifications prospective, Atom 230 is quite up-to-date. It uses 533MHz system bus, supports SSE3 instructions and even 64-bit Intel 64 extensions.

Besides Atom 230, the Intel nettop processor lineup includes one more solution – Atom 330. It is a dual-core processor deigned as two Diamondville semiconductor dies placed onto the same processor board. As a result, Atom 330 has the same specifications as Atom 230, but it has two cores instead of one. Even its clock frequency equals the same 1.6GHz. Its TDP is certainly twice as high: the dual-core processor dissipates 8W of heat.

 

VIA Nano

Having launched processors with x86 microarchitecture for ultra-portable devices, Intel will have to compete not against their eternal rival, AMD, but against VIA that occupied this market niche a few years ago after successful acquisition of “second-tier” processor developers – Cytrix and Centaur. The latest VIA’s solution that has every chance to become a worthy rival to Intel Atom is Nano processor, the first representative of the new Isaiah microarchitecture developed by Centaur technology engineers from scratch.

Although VIA formally positions Nano processor as a continuation to their C7 family and is even pin-compatible with it, this processor is based on a completely new microarchitecture. Nano is VIA’s first processor with out-of-order instructions execution, which Intel has given up in their Atom CPUs for the sake of better energy-efficiency. Nevertheless, although Nano does have all the features of contemporary x86 processors, such as branch prediction algorithms and speculative instructions execution, its TDP lies within the standards for nettops, netbooks and even ultra-portable Internet terminals.

The other side to this relatively complex microarchitecture is higher typical heat dissipation than that of Atom. VIA Nano will have to work at less than 1GHz frequency in order to dissipate 4W of heat like Atom 230. However, even a CPU with out-of-order execution will not be running fast enough at this frequency. Therefore, VIA is offering nettop processors with much higher TDP than that of Intel’s solution: 8W, 17W and even 25W. In other words, it is impossible to directly compare VIA Nano and Intel Atom: these are processors from different “weight categories”.

In this respect, it is not surprising that Isaiah microarchitecture is more similar to Core than to Atom. However, the number of decoders and execution units still make Isaiah inferior to Core. Nano processors can execute three instructions per clock cycle and have 7 execution units: two integer units, two units for SSE and FP operations and three units for work with memory. Here I would like to specifically point out that the implementation of their floating-point units is much more efficient: they can perform widely spread addition and multiplication operations within fewer clock cycles than Intel Core 2 processors. At the same time Isaiah microarchitecture uses a number of contemporary technologies improving processor efficiency even more. For example, Nano processors use analogous macro- and micro-ops fusion approach to instructions decoding and support memory disambiguation technology that allows reordering memory operations.

When VIA engineers launched their new microarchitecture, they made sure that it complied with all contemporary processor requirements. Therefore, Nano became not only the first superscalar VIA CPU with out-of-order instructions execution, but also the company’s first processor supporting 64-bit extensions of x86 architecture. The CPU also has SSE3 instructions set. At the same time, they didn’t forget about a distinguishing feature of all VIA CPUs: additional PadLock unit that provided hardware acceleration of AES encoding/decoding and SHA-1 and SHA-2 cryptographic hashing calculations.

However, Isaiah microarchitecture remained single-core and single-threaded. Nano family doesn’t include any dual-core models and there is nothing in these processors pointing that SMT is even possible. However, VIA doesn’t exclude the possibility of upgrading the microarchitecture later on for the purpose of launching multi-core processors. However, it may only happen when they move to a new manufacturing process.

In the meanwhile VIA Nano is made using not the most advanced 65nm production process. However, it still allows making physically small dies: Nano’s die size is only 63sq.mm. The semiconductor processor die consists of 94 million transistors and is bigger part is given to cache-memory, which is pretty big on Nano. L2 cache is 1MB big, and L1 cache is 128KB split equally between instructions and data. Note that Nano has exclusive cache-memory, i.e. the data stored in L1 cache is not duplicated in L2, which makes the CPU work more efficiently with the memory.

As for the clock frequencies, Nano processor family includes several models working at frequencies from 1.0GHz to 1.8GHz and supporting 800MHz or 533MHz VIA V4 system bus. Nano L processors are targeted for mainstream power-efficient desktop and mobile systems, while U series with lower core voltage is intended for mini form-factor and ultra-mobile systems.

I would like to point out that although Nano looks like a regular desktop processor, VIA engineers paid special attention to its power efficiency. And even though it loses significantly to Intel Atom in typical heat dissipation, the performance-per-watt aspect doesn’t make conclusions so simple any more. Due to unique technological solutions, supported wide range of power-saving modes and voltage regulation depending on the core temperature Nano belongs to power-efficient processor category. It is important to keep in mind here that once VIA switches to 45nm production process in H2 2009 the heat dissipation and power consumption rates of its processors will inevitably improve.

Mini-ITX Nettop Platforms

Although many mainboard manufacturers will undoubtedly introduce their own platforms for miniature PCs, we decided to dwell on reference solutions that Intel and VIA offer together with their low-power processors.  As a result, we are going to talk about two Intel mainboards with embedded Atom processors and one VIA mainboard with embedded Nano processor Let’s take a closer look at these solutions now.

Intel D945GCLF

Intel’s desire to win the netbook and nettop market found its way not only in specialized processor microarchitecture. Together with the new Atom they also introduced a few platforms of their own proprietary design that include a mainboard with an integrated Atom processor. We tested several mainboards like that when working on this review. One of them was D945GCLF with Atom 230 processor.

As we have already mentioned above, this process targeted specifically for nettop devices works at 1.6GHz frequency and supports 533MHz system bus. Its Vcore is set at 1.1V and typical heat dissipation equals 4W.

CPU-Z utility reports the following about this processor:

 

Due to Hyper-Threading support the system sees this single-core processor as two virtual cores:

 

Intel nettop concept implies that Atom processors should be used together with Intel 945GC core logic equipped with an integrated Intel GMA950 graphics core. This particular chipset is used in Intel D945GCLF mainboard. However, this mainboard doesn’t reveal its features and functionality to the full extent. Namely it doesn’t have PCI Express x16 graphics slot and has only one DDR2 SDRAM DIMM, although Intel 945GC supports external graphics cards and dual-channel memory access. Looks like Intel tried to make D945GCLF cheaper this way. And they did succeed. This mainboard with the integrated CPU and GPU retails at around $70-$80.

GMA950 graphics core available on this platform supports DirectX 9.0 and works perfectly fine with Windows Vista Aero interface. Unfortunately, it has very limited functionality for video playback, so there is no way to take workload off the CPU during HD content playback.  As for 3D performance, GMA950 has four pixel pipelines working at 400MHz frequency, which is pretty good for entry-level integrated graphics. However, since it uses part of the D945GCLF system memory working in single-channel mode for video needs, it is hardly possible to use the integrated Intel 945GC graphics accelerator in 3D mode.

Another frustrating thing: there is only analog D-Sub out on this board. It would be impossible to connect any monitors to D945GCLF using digital interface.

ICH7 South Bridge is responsible for supporting peripheral and external devices. It provides two SATA 3Gbps ports and a PATA port and the rear panel contains a pretty extensive variety of connectors. Among them are 4 USB 2.0 ports (two more are laid out as pin-connectors), 100Mbit network port, parallel and serial ports, PS/2 connectors for keyboard and mouse and three analog audio-jacks. To be fair I have to say that they also used a Realtek ALC662 HD codec for the sound tract.

Keeping in mind that nettops are first of all very small systems, Intel engineers designed their D945GCLF platform in Mini-ITX form-factor that was introduced a few years ago by VIA. So, this board measures 17x17cm.

The number of expansion slots on this board is minimal. Besides one DDR2 DIMM slot, there is only one single PCI slot. However, it is more than enough for a highly integrated solution like D945GCLF.

A system built around D945GCLF platform requires a regular power supply unit of small capacity. The mainboard is equipped with two standard power connectors: a 20-pin and a 4-pin one. Both of them need to be connected to the PSU.

The cooling system on D945GCLF is pretty primitive. The processor is cooled with a miniature aluminum pin-heatsink. The chipset North Bridge is manufactured with relatively old 90nm process and has typical heat dissipation of 22W. As a result, it needs active cooling. Even a small cooler with a fan would do. ICH7 chip does just fine without any heatsink at all.

Intel D945GCLF2

Intel D945GCLF2 platform is almost the same as Intel D945GCLF we have just discussed. However, there are a few minor but very important differences.

Although both platforms use absolutely the same mainboards, D945GCLF2 has a newer integrated processor – Atom 330. This CPU differs significantly from Atom 230: it is a dual-core processor. Other technical specs of this processor remained the same. It works at 1.6GHz frequency and supports 533MHz system bus.

As a result, the report we get from CPU-Z identification utility launched on D945GCLF2 is very similar to what we have just seen:

 

The last version of CPU-Z doesn’t know dual-core Atom very well. As we see, it doesn’t recognize the processor model number correctly.

Dual-core Atom 330 processor has very simple internal structure: Intel used the same approach as for 65nm Pentium D. the CPU consists of two independent cores within the same package. In other words, Atom 330 is a combination of two Atom 230 processors. That is why his dual-core CPU supporting Hyper-Threading is represented as four virtual cores in the system:

Quite logical that the typical heat dissipation of Atom 330 processor is twice as high and equals 8W. However, this processor on Intel D945GCLF2 mainboard didn’t acquire an active cooler. Its heatsink just got taller:

There is a small heatsink with a fan on top of the chipset North Bridge that heats up three times more than a low-power dual-core processor.

Intel D945GCLF2 mainboard has one more less significant difference from D945GCLF. It has a TV-Out. Other functionality of both platforms is absolutely identical.

VIA Nano Reference Board

We managed to test VIA Nano processor thanks to a reference board with it that our lab received for a few days. The board turned out none other but a well-known EPIA SN with a new VIA Nano processor instead of the traditional C7. It was totally possible because both these processors are pin-compatible. Nevertheless, I have to stress that there won’t be EPIA SN platform with a Nano processor in the mass market, because VIA is working on a new mainboard for this processor. However, this bundle will do just fine for our today’s preview purposes.

We checked out a platform with the fastest CPU available that worked at 1.8GHz. This processor uses 800MHz system bus, works at 1.2V Vcore and has typical TDP of 25W.

The diagnostic utility provided pretty detailed report, however didn’t recognize the model number - L2100:

 

The reference board is built on a VIA CN896 North Bridge and VIA VT8251 South Bridge. The North Bridge provides VIA V4 processor bus, single-channel DDR2 SDRAM and PCI Express bus. Moreover, the North Bridge features VIA Chrome6 HC IGP integrated graphics core. This core has two pixel pipelines and works at 250MHz frequency. It can use up to 256MB of memory dynamically assigned to it from the system memory.

Despite the claimed DirectX 9.0 support, the graphics core built into VIA CN896 is not compatible with Windows Vista Aero interface. The base modification of this board has only an analog monitor D-Sub out, however there is a connector for a daughter card with DVI interface on the mainboard PCB. Besides, EPIA SN also supports external graphics cards and has a PCI Express x16 slot for that.

VIA VT8251 South Bridge is responsible for all peripherals. EPIA SN supports up to 4 SATA 3Gbps hard drives (with RAID support), two PATA devices and has 6 USB 2.0 ports, four of which are on the rear panel. There are also two Fast Ethernet ports, a serial port, PS/2 connectors for keyboard and mouse and three analog audio-jacks implemented by VIA VT1708A HD codec.

The reference board is designed in Mini-ITX form-factor and measures 17x17mm:

I have to say that EPIA SN has much richer expansion functionality than Intel mainboards for Atom processors. Besides the PCI Express x16 slot, there are two DDR2 DIMMs. As a result, EPIA SN supports up to 4GB of memory.

Besides that, there are two more interfaces typical primarily of mobile systems on the reverse side of the PCB: Compact Flash and Mini PCI slots:

Another peculiarity of the EPIA SN platform is a single 20-pin ATX power supply connector. It uses only one power cable and doesn’t require additional 12V power lines.

The processor and chipset North Bridge are cooled with a single aluminum heatsink with a small fan in the center. The configuration of this cooler reminds us of the slot Pentium II and Pentium II processors. The South Bridge is cooled with a primitive aluminum heatsink.

Testbeds Configuration

The main goal of our today’s test session was to study the potential of platforms positioned for nettop devices – small inexpensive and power-efficient computers used primarily for Internet surfing and work with Internet applications. All three above described platforms participated in our test session: Intel Atom 230, Intel Atom 330 and VIA Nano L2100.

However, we wouldn’t be able to get a complete picture of the consumer functionality of processors with new microarchitectures by simply comparing these three platforms against one another. Therefore, we included two more systems based on the cheapest and slowest LGA775 processors from Celeron family based on Core microarchitecture: Celeron 420 and Celeron E1200. Both these CPUs work at 1.6GHz frequency, the same as Atom. The only difference between them is in the number of cores: Celeron 420 is a single-core processor, while Celeron E1200 – a dual-core one. However, Celeron 420 retails at about the same price as Atom 230 ($29), while the official price for Celeron E1200 is set at the same exact number as that for Atom 330 ($43).

To ensure a fair comparison between Atom and Celeron based platforms we used an LGA775 mainboard on Intel 945GC chipset used for D945GCLF and D945GCLF2. It was ASUS P5GC-MX/1333. For the sake of fair competition we enabled only one memory channel on it.

As a result, our testbeds were configured as follows:

We performed all tests on Microsoft Windows Vista x86 SP1 operating system. Despite a widely spread opinion, nettop processors are powerful enough for this OS to run normally. For example, Vista reported a pretty average Windows Experience Index on Intel D945GCLF platform with an Atom 230 (the slowest of all tested processors).

Processor Comparative Specification Chart

 

Performance

General Performance: PCMark Vantage

To get an idea about the average platforms performance under various types of workload we used PCMark vantage test that provides a number of different analysis approaches.

The total score is calculated from the systems performance in single- and multi-threaded general purpose applications typical of home PCs. Dual-core Celeron E1200 is the fastest here. The second fastest is dual-core Atom 330 that outperforms all single-core testing participants. VIA Nano L2100 runs as fast as the youngest Celeron 420 on Core microarchitecture leaving Atom 230 far behind. Since all processors except Nano work at the same 1.6GHz frequency, the obtained results illustrate perfectly the simplicity of Atom 2-Issue and In-Order microarchitecture.

Memories pattern estimates the systems performance during work with a digital media archive of pictures and home videos. The situation doesn’t really change that much under this type of processor workload. Dual-core Atom 330 is the only low-power processor to outperform the youngest single-core Celeron 420 on 65nm Conroe-L core based on Core microarchitecture. However, even in this case the performance difference doesn’t exceed 10%. It once again proves that Intel and VIA’s new microarchitectures for nettop devices are not intended to hit any significant performance heights.

TV and Movies test uses HD video playback and decoding. The processor’s ability to work in multi-threaded mode matters most here. A single-core VIA Nano L2100 rolls back to the last place: even Atom 230 working at a lower frequency shows better results. Although it has only one core, it supports Hyper-Threading. However, it still can’t catch up with Celeron 420: Core microarchitecture is much more progressive. However, dual-core Atom 330 performs very well here: it is only 10% slower than dual-core Celeron E1200.

Gaming patterns tests the platforms in 3D gaming applications. That is why the results turned out so low. The workload here falls not only on the CPU, but also on the graphics cores. And they are evident weaknesses of the today’ testing participants. The thing is that integrated graphics accelerators also use system memory, which in our platforms works in very slow single-channel mode.

Music pattern deals with audio files encoding into different formats. The results are quite typical here. Nettop processors lose even to the youngest LGA775 CPUs. VIA Nano L2100, however, does pretty well: it is 16% faster than Atom 230, but 4% slower than Atom 330.

These results are obtained under typical Internet workload, which is exactly what Intel Atom and VIA Nano were developed for. The test emulates internet surfing, work with e-mail client and IP-phone. The obtained results suggest that systems built on contemporary Celeron processors cope with this type of tasks way better than new nettop solutions. As for the new low-power solutions, the fastest here is Atom 330 with Nano L2100 following close behind. However, you should keep in mind that it is not only the performance that matters here, but also power-consumption, which we are going to discuss later on. In reality, all processors including the slowest Atom 230 are fast enough to ensure comfortable Internet-experience.

Productivity is another simple pattern emulating work in typical office applications. As we see from the obtained results, Atom and Nano processors compete successfully against Celeron 420 that is often used for office systems these days. In other words, nettops may find their way not only into homes but also into office environments.

Office Applications and Internet

Besides complex benchmarks, we always use real applications to study the systems performance. Taking into account nettops positioning, we decided to check the performance of the corresponding platforms in a popular Microsoft Office 2007 suite. For testing purposes we chose document comparison in Word and complex table calculation in Excel.

The results turned out completely different. VIA processor outperformed both Atom CPUs and a single-core Celeron in Word. However, its performance in arithmetic calculations turned out very poor, while both Atom processors performance very well (compared to Celeron).

We also decided to see how well our today’s testing participants will perform in Adobe Flash. Very often the CPU’s ability to playback flash movies determines the actual CPU utilization during web-surfing. For that purpose we used a special Powerflasher Powerbench test.

As you can see from the diagram, Celeron processors on Core microarchitecture perform better during Flash playback than Atom or Nano. For example, Celeron 420 appears 60% faster than the youngest Atom 230. Atom 330 falls 38% behind the same Celeron. Only VIA Nano processor demonstrates comparable results to Celeron 420 and loses only 12% to it.

Video Playback

Since nettops are also positioned as home PCs, many users will definitely try playing videos on them. Therefore, we decided to check if Atom and Nano will prove powerful enough to play HD videos with acceptable quality.

In this test we measured the fps rate during 720p and 1080p playback of H.264/AVC and WMV3 videos. If we see 24 fps, it means no frames are lost and the CPU copes with the workload successfully. Otherwise, we can estimate how much power the processor is lacking for quality video playback. We used “Dark Knight” movie trailer as an example of HD media content. We used ffdshow codec as one of the fastest and most widely spread codecs.

Before we move on to the results, I would like to add that graphics cores integrated into Intel 945GC and VIA CN896 chipsets do not support hardware acceleration of HD video decoding. Therefore, it is the CPU that has to do all the work.

Well, looks like Intel Atom and VIA Nano are not fast enough to ensure quality playback of HD video content. However, I have to make a few clarifications to this uncompromising verdict. Nettop platforms only fail to cope with 1080p videos. 720p format is displayed perfectly fine with any CPU, even a single-core VIA Nano L2100 work just fine here, not to mention Atom 230. The CPU utilization graph below was taken on a system with Intel Atom 230 during H.264/AVC movie playback at 720p resolution:

If we do not take into account both Celeron processors that cope almost impeccably with HD video playback, then the winner will be Atom 330. This result proves once again that multi-threading is indeed very useful for video decoding tasks. Therefore, Atom 230 outperforms VIA Nano L2100 that theoretically has more progressive microarchitecture.

Other Applications

We decided to give up a lot of benchmarks that we would normally use for CPU tests, because nettop processors are pretty specific solutions. Computer systems of this type will hardly ever be used for image rendering, 3D games or video mastering. Therefore, we performed only a few most typical tests.

Audio encoding into mp3 format demonstrates how little computational potential these processors have. They lose even to Celeron 420. Nevertheless, the results demonstrated by Nano L2100 look very interesting: it outperforms even a dual-core Atom processor!

The situation changes a little during video decoding: dual-core Atom 330 with Hyper-Threading support is only 7% behind Celeron 420. Single-core nettop processors can’t successfully compete even with Celeron 420.

We see almost the same results during WinRAR archiving.

Chess test, like many others, reveals significant advantage of VIA Nano L2100 processor over Intel Atom 230. However a newer Atom 330 doesn’t lose to VIA anymore.

We performed a Half-Life 2 test just for the sake of a complete picture. In fact, it is very hard to play contemporary games on any of the today’s tested platforms because of low performance of the graphics subsystem. The obtained results simply show that low-power processors are not the best choice for gaming.

Synthetic Benchmarks – SiSoftware Sandra 2009

In conclusion to our performance tests we decided to offer you the results of a synthetic Sandra 2009 benchmark. They show how different microarchitectures work with certain type of instructions.

Power Consumption

Low power consumption is the main advantage of nettop processors, at least that’s what the manufacturers claim. To check how true this statement actually is we measured the power consumption of all our today’s testing participants. We measured the power consumption of complete systems without the monitor under different types of workload. But first of all let’s take a look at systems power consumption in idle mode:

Atom based platforms proved extremely economical. Although they use Intel 945GC chipset that is not a low-power solution, Intel D945GCLF2 and Intel D945GCLF consume less power than the other platforms. However, the systems with desktop Intel Celeron processors do not look that bad at all. The difference between a platform on Intel Atom with 4W typical TDP and a platform on Intel Celeron E1200 with 65W typical TDP is only 10W in idle mode. The picture becomes more illustrative once we increase the workload.

The results on the next diagram were taken during playback of a H.264/AVC movie in 480p resolution:

Although video playback and decoding seems to be a pretty easy task, it loads slow nettop processors quite noticeably. Therefore, the power consumption readings increase significantly compared with the idle numbers. Nevertheless, Atom processors once again prove that they are indeed low-power solutions. They consume the least power during video decoding. Here I would also like to point out that Celeron 420 performed really well, too. Although this processor is based on pretty “ordinary” Core microarchitecture without any special optimizations lowering its power consumption and heat dissipation, it consumed only 6W more than a single-core Atom processor. This way Celeron 420 turned out even more efficient than VIA Nano L2100.

The nest measurement was taken when visiting a web-site with Flash-base design that loads the CPU significantly:

As you can see from the diagram above, Flash may be harder on processors than video. However, the overall picture remains the same. The most power-efficient processors here are Intel Atom, both single- and dual-core ones. VIA Nano L2100 that is positioned as their primary competitor turns out much less efficient and loses even to Celeron 420. This poses serious concerns about high consumer qualities of VIA solution that turns out slower and more power0hungry than the youngest desktop CPU from Intel.

In conclusion we would like to offer maximum power consumption measurements that were taken during Prime95 utility run, as always:

Atom 230 based platform again boasts minimal power consumption. Under maximum workload it wins almost 12W from a system with Celeron 420. Dual-core Atom 330 also proved pretty power-efficient: it consumes 7W less than a system with the youngest Celeron on Core microarchitecture. However, the results demonstrated by Nano L2100 processor are a bit upsetting. Not only can’t it compete with Intel’s new processors in terms of power efficiency, but also loses to Celeron 420. As a result, the best performance-per-watt rate among contemporary nettop offerings belongs to Atom 330.

Conclusion

Well, this was our first look at contemporary platforms for nettops – small, inexpensive, power-efficient and quiet home systems. We got an idea of new processor microarchitectures and platforms designed for solutions of this type. Overall, we can say that highly integrated solutions from Intel and VIA that never consume over 70W of power and offer pretty sufficient performance for a wide range of tasks a home user would ever need to work with. New generation of low-power platforms not only work with Internet applications in Windows Vista OS, but are also powerful enough for more resource-demanding tasks, such as office applications and HD video playback (with a few limitations). All this indicates that nettops do have a future, especially since computer systems like that attract the users not only due to their power-efficiency, quiet operation and small size, but also due to their very affordable price resulting from low-cost components.

What existing processor would be preferable for a nettop computer? This is a pretty complicated question and the answers to it will be different depending on the criteria priorities. If low cost and low power consumption are most important for you, then Atom 230 will be the best choice. However, if you care more for performance-per-watt, then you should go with a dual-core Atom 330. Even a regular Celeron 420 on Conroe-L core performed quite well. It is not as economical as CPUs on Atom microarchitecture, but it can provide decent performance at reasonable power consumption level.

VIA Nano processor that seems to have yielded to Atom 330 and Celeron 420 processors in many aspects also has its indisputable strengths. VIA’s primary advantage is very smart design of EPIA platforms that offer mush more functionality and integration than Intel solutions. Moreover, new Isaiah microarchitecture performs fast enough, so you shouldn’t really charge it off just yet.

However, Atom and Nano based nettops the way they are today will hardly become sales hits like netbooks, for instance. Unfortunately, they are not powerful enough to become a fully fledged home PC. These CPUs will not be able to playback HD movies at 1080p resolution and it will most likely discourage most potential customers. Nevertheless, new low-power processors will be coming out shortly and then we will certainly be more confident about the future of the new class of computer devices.