Chaintech Enters the SFF PC Market: IMO-Desk I651U Review

Chaintech introduced a new concept of a small home PC: a home desktop system with a notebook design. Today we are going to find out if this idea has been put into life successfully and will introduce to you the first representative of the IMO-Desk family for Pentium 4 processors designed on SiS651 chipset. Please meet the solution, which is claimed to be "the Smallest Desktop in the World"!

by Ilya Gavrichenkov
02/17/2004 | 08:17 PM

Today’s computer market is not what it used to be just a couple of years ago. Computers are catching up with household electronics, getting as popular and widely spread as consumer devices. And this tendency has provoked an ever-increasing demand for computers with specific configuration. We used to split PCs into two categories: office machines and high-performance stations for gamers and enthusiasts. But now there has emerged a third class: home computers. Owners of such systems usually use them for processing multimedia content and for surfing the Web rather than for hardcore gaming.


Demand gave birth to supply of home-targeted computers with such distinctive features as low price, small size, stylish design and low noise level. Many manufacturers of computer parts have followed the trend by offering barebone systems like those “cube” systems we meet (and review) so often nowadays. As the trend strengthens, we are likely to see more innovations in this area in 2004. Recently we reviewed a non-standard home multimedia computer ASUS DIGIMatrix (see our article called ASUS DIGIMatrix Review: Computer Systems Invade Consumer Electronics Market) and now we have something completely new coming from Chaintech.

Chaintech has earned respect as a manufacturer of mainboards and graphics cards. Last year the company adjusted its marketing policy and started producing special mainboards sharpened at enthusiasts. The home user shouldn’t feel forgotten, though, as the company has recently unveiled their original barebone system called IMO-Desk designed specifically for the home users’ needs. The manufacturer describes the product as “Mini Desktop PC”, but it looks quite weird at first sight. Let’s get acquainted with this new type of SFF systems now!

IMO-Desk Concept

So, what is IMO-Desk? The “IMO” in “IMO-Desk” stands for “Internet, Multimedia, Office”. So we are supposed to deal with another version of the home computer concept, a PC you use for surfing the Internet, for all your office needs and for working in multimedia applications. You may get the impression that it is just another variation of the “cube” system? No, you are absolutely wrong here. First of all, take a look at this box, and you will see what I am talking about:

If you haven’t read the introductory part of this article, you may have thought this is an ordinary notebook. Well, it’s not quite a notebook. I would even say it is not a notebook at all! This computer is not mobile as it uses ordinary desktop parts and has no battery. The IMO-Desk resembles the Desknote from ECS in this respect, but Chaintech has some other idea behind it.

The IMO-Desk is not a portable computer. Well, you can, of course, transport it anywhere, but the manufacturer implies that you use it as a stationary computer. On the other hand, the “notebook” form-factor means compactness, which is important for home or office use. Besides that, the IMO-Desk is the only barebone system to come equipped with a monitor (that’s good for an inexperienced user – no bother about the monitor at all).

In spite of the exterior resembling that of a large notebook, the IMO-Desk will be assembled with an ordinary (not mobile!) processor, hard disk drive and memory. Of course, this makes the box heavier and larger, but this is not critical – the concept says you shouldn’t carry the IMO-Desk far away. At the same time, we get the whole bunch of bonuses instead: the assembled PC is cheaper, as desktop parts cost less than similar parts for mobile computers, and sometimes this price difference is quite tangible. Desktop parts also boast better characteristics such as higher HDD storage capacities and faster processor and memory performance. The power consumption is higher too than by a notebook, but that’s again not important: Chaintech reminds us once again that the IMO-Desk is a stationary desktop system.

The same things are true for the LCD monitor the IMO-Desk comes with. The manufacturer didn’t strive for the power consumption minimization, so we have an ordinary matrix like those you see in a typical LCD monitor and such pleasant things like better color reproduction, lower response time, wider viewing angles and higher brightness (double number of backlight lamps!).

So while the ordinary notebook is a mobile computer, and the Desknote from ECS is a mobile computer you can’t use on the go, the IMO-Desk from Chaintech is a stationary computer, just pretending to look like a notebook.

Now that we’ve grasped the concept, let’s discuss its particular implementation.

Specification and Accessories

The first IMO-Desk model from Chaintech is based on the SiS651 chipset and is designed to support Socket 478 processors. The model name is I651U. Its characteristics are listed below, right now I just want to tell you that Chaintech is planning to roll out the entire family of IMO-Desk systems for Pentium 4 as well as for Athlon XP and even Athlon 64 processors. Accordingly, there will be different chipsets from the whole gang: ATI, VIA, NVIDIA, SiS and Intel. So if things go right, Chaintech will be offering a wide range of original SFF PCs like Shuttle is offering its numerous cubic systems now.

And now the promised specifications of the IMO-Desk I651U:

A WLAN card (802.11a/b protocol) is optional for the IMO-Desk I651U, but we didn’t have it in our system. Besides the barebone itself, you receive the necessary documentation, a CD with drivers, a remote control unit and an external power supply unit that outputs a current of 20W, 6A.

IMO-Desk: a Look from the Outside

Let’s approach the IMO-Desk I651U from the outside. Here it is closed:

When closed, the system doesn’t snap shut as notebooks do, but again it is normal as you are not supposed to travel with it. As for the design of the system, it is rather questionable. There are no strict forms: the striped cover has vent holes in it and a bump in the center. This is hardly a perfect design solution, but we have to put up with it as it is forced by the ordinary desktop LCD matrix, which is used in this evice.

People from Chaintech said the quality of the plastic used for the system case would be different and better in off-the-shelf systems (we have received a pre-release sample), but I actually have no complaints about the material of the pre-release version already.

And this is the front panel of the IMO-Desk I651U:

The speakers are hidden behind the decoration grid. They are no hi-fi ones of course, but they are a way better than average “notebook” audio systems. Meanwhile, the IMO-Desk I651U offers you six-channel sound, so you may want to use an external speaker system with it. Next to the right speaker there are two jacks for connecting the headphones and a microphone. By the way, there is also an integrated microphone, buried deep inside the system that is why I will dwell on it a little bit later in our review.

There is a ventilation hole is in the center of the panel, and above it there is the card-reader and the IR port (for the remote control unit).

The front panel also carries two indicators: one is showing the card-reader activity, and the other lights up when you press a button on the remote control.

The right panel of the system carries two USB 2.0 ports (for some mysterious reason, they are placed upside down), an optical drive of the “slim” form-factor (the only component the IMO-Desk I651U has borrowed from mobile computers), and two IEEE1394 ports (4-pin and 6-pin). There is also an exhaust vent hole, where the warm air is blown outside the system case.

The left panel carries two more “upside-down” USB 2.0 ports, an infrared IrDA port, a vent hole for the HDD, two audio jacks and an optical S/PDIF output. You can live happily with the USB ports being upside down, but the audio outputs at your left hand are definitely not the most convenient thing. If you connect an external speaker system to the IMO-Desk, the cables will be lying on your desk, right under your hand, which you will hardly like that much.

Let’s now take a look at the rear panel.

This is a real horn of plenty! Look at all these I/O ports (from left to right). Here we find a PS/2 port for connecting a mouse or keyboard (if you don’t feel comfortable with the standard 88-key keyboard and the touchpad of the IMO-Desk), an RJ45 connector for a wired network, an S-Video input and an output for an external monitor, two legacy ports (serial and parallel) we hadn’t expected to find in this system, a PSU connector, an RJ-11 modem plug for the phone line, and the line-out jack. On the right of the back panel there is a grid through which the CPU cooler blows hot air out.

The IMO-Desk I651U is overloaded with various connectors and their placement may not be too convenient, as you may have noticed. On the other hand, it has everything necessary to connect any peripheral device you may want to use. A WLAN controller is missing in our sample, but it is an option you may find in other systems of the kind.

Easy to Use?

Let’s try the thing in practice. I realize most users will use it with an external mouse, keyboard and monitor, but I am going to trying finding out how you would feel using the IMO-Desk I651U without any externals.

Let’s start with the LCD matrix. The IMO-Desk I651U comes with a fully-fledged LCD monitor with a 15-inch diagonal and 1024x768 resolution. It differs positively from LCD matrixes of ordinary notebooks. It reproduces colors naturally, and its brightness is nearly twice as high as that of an average notebook LCD panel. The response time is up to the mark, too, while the viewing angles are simply good (120° horizontal and 100° vertical). That’s what a multimedia system should be like: you can watch a movie in a company of your friends and people who look at the screen at a small angle will see everything properly, without any noticeable distortions.

The integrated audio subsystem is of pretty average quality. You can’t expect the two small speakers to represent the entire frequency range, especially basses, but they reproduce the audio picture at large quite normally.

The 88-key keyboard resembles those of many notebooks, but with larger keys as the IMO-Desk I651U is generally larger than notebooks. They are even larger than keys on some ordinary “desktop” keyboards, which will definitely please the users with large fingers. Besides, the keys are soft, easy to press. Overall, it is a nice comfortable keyboard.

The IMO-Desk I651U offers you a touchpad instead of the mouse. The working surface of the touchpad is pushed into the case to prevent it from a casual touch. There are two buttons below the sensitive area and there is also a microphone input hole at the lower left corner of the touchpad.

Indicators are placed to the left of the keyboard. There you can find a bright yellow power-on light and a few green LEDs indicating the system status (suspend mode), HDD activity, and showing if you enabled caps lock, scroll lock or num lock.

The power button is located below the keyboard, next to the keys that launch your browser and e-mail client, eject the optical drive, and reset the system. There are also two programmable buttons, which you can assign your own functions.

Although the IMO-Desk I651U is positioned by Chaintech as a home PC for multimedia applications and Internet surfing, the system is not bundled with any specific software. The only utility you receive with this computer is for programming the software keys. Besides, you can also download a special DigiDoc utility for system status monitoring from Chaintech company site. However, this is not exactly what we were looking for. We expected an operation system and a DVD player at least, as the system comes with a DVD-ROM. It would also be great if they shipped some unified interface for multimedia content processing, which could be easy to work with even for unsophisticated users.

Maybe the system integrators (who will assemble these systems) will create a software bundle for the IMO-Desk, but the manufacturer of the platform offers no unified solution. However, this is a common problem of all SFF PCs manufacturers, who regard their customers as mainboard buyers, although the latter type of users usually have more computer-related experience.

I would like to add in this respect that luckily the situation with Chaintech IMO-Desk is not so hopeless. The company representatives told us that Chaintech engineering team is working hard on the problem and by the time the solution starts shipping in mass quantities, IMO-Desk should already acquire unified software interface for audio and video playback.


The manufacturer ships IMO-Desk I651U as a barebone system: without processor, memory and hard disk drive. To install these components, you remove two covers at the bottom of the case, which are fastened with four screws and clips. With the covers removed, you will have no problems accessing the slots and bays.

Regrettably, it’s not that easy to get to the single mini-PCI slot. The user’s manual doesn’t mention this slot at all, and we couldn’t find an easy way to reach it either. In fact, if you want to plug a mini-PCI card into the IMO-Desk I651U, you will have to take the whole system apart, which is not a trivial job. Thus, we suppose the mini-PCI slot of the IMO-Desk I651U is intended for installation of optional cards back at the factory. Ordinary users are in fact deprived of the upgrade options here and will hardly be able to install any additional peripheral devices into this slot.


As I have mentioned above, the IMO-Desk I651U contains a mainboard based on SiS651 chipset. The chipset supports DDR SDRAM working at 100, 133 or 166MHz and Pentium 4 and Celeron processors with 400 or 533MHz FSB frequencies. The CPU voltage regulator of the IMO-Desk I651U doesn’t support processors on the old Willamette core, you can only use Northwood based processors here (the Prescott is not supported for heat dissipation reasons).

The chipset includes integrated SiS315 graphics core that can use up to 64MB of the system RAM as graphics memory. The features of this core are enhanced in the IMO-Desk I651U by means of a SiS301LV companion chip, which is responsible for the DVI output to the LCD panel and for TV-out implementation. By the way, the remarkable feature of the SiS301 chip is the fact that it turns off the LCD panel once the TV-Out is activated.

The South Bridge of the chipset is the SiS962 chip that guarantees support of IDE devices (a HDD and an optical drive), four USB 2.0 ports, 10/100Mbit Ethernet, support for keyboard and mouse. The sound and modem are also implemented in the same South Bridge with the help of a few physical controllers: Realtek ALC650 and PC Tel PCT303. Two more USB ports are not laid out at the rear panel: they are used to connect the card-reader and the IR receiver of the remote control unit.

An external Realtek RTL8801B PCI controller supports two IEEE1394 ports. ITE IT8705F chip is responsible for controlling the fans, for monitoring and supporting the legacy I/O ports.

Cooling System and Temperatures

The cooling system of this barebone is a very curious thing to us. The thing is that although IMO-Desk is just a little bigger than a notebook, its cooling system should be efficient enough to cool down ordinary desktop parts (including the CPU and the HDD), which dissipate quite a bit of heat. On the other hand, many notebook manufacturers sometimes use ordinary desktop processors in their products and do not face any grave problems, so there is nothing extraordinary about this cooling system.

The IMO-Desk I651U is cooled down by a pair of fans, one of which is blowing the air through the CPU heatsink, while the other is fastened onto the chipset heatsink. Both fans take hot air from inside and blow it outside the case. Before getting to the fan blades, this air takes a long trip through the case, around other system components such as hard disk drive and memory module. Thus an acceptable thermal environment for the system is created.

Both fans have a small diameter and variable rotational speed that depends on the temperature inside the IMO-Desk I651U. In some cases, the fans may be stopped completely. That’s why this computer works noiselessly under low workloads, but becomes louder as the workload increases to the full. The noise from the IMO-Desk I651U is no louder than the noise coming from any desktop system, though I should admit that it has a different and rather annoying tonality. So, I won’t say that the IMO-Desk I651U is always noiseless. It depends on what you do with it.

As for the efficiency of the used cooling solution, I didn’t reveal any issues about it. Both coolers use the heat pipe technology for transferring heat. This is what the CPU cooler looks like:

It handles successfully such powerful processors as Intel Pentium 4 2.53GHz (at least we ran our full set of benchmarks without any problems) although the specification says the topmost supported CPU is 2.4GHz. Like with other SFF PCs, I had some concerns about the HDD temperature, which was sometimes as high as 50°C and more. This temperature may shorten the life term of your HDD, so you’d better use a drive, which is more tolerant to high temperatures.

In order to illustrate the thermal conditions inside Chaintech IMO-Desk I651U system in idle and burn modes, we would like to offer you the next table. We assembled the system with an Intel Pentium 4 2.53GHz, a 256MB module of DDR333 SDRAM and a Western Digital WD400JB HDD and warmed it up by running the CPUBurn utility and the Business Winstone 2004 benchmarking package:




CPU temperature, oC



System temperature, oC



HDD temperature, oC



First fan rotation speed, rpm



Second fan rotation speed, rpm



So, the thermal environment should be considered acceptable (although the high temperature of the HDD certainly reduces its service time). Besides that, you can use only Pentium 4 and Celeron processors in the IMO-Desk I651U, and these processors can take care of themselves in case of an imminent overheating accident. So you shouldn’t be concerned with the reliable functioning of the system.


When you will be looking through the test results you should realize the fact that systems like Chaintech IMO-Desk I651U don’t necessarily need to be fast. The purpose of this mini-system is to be a home computer for playing videos and music, for working in the Internet and using office applications; it’s clear you don’t need much processing power for such tasks. Chaintech IMO-Desk I651U won’t suit you as a gaming station: the integrated SiS315 graphics is far from being a perfect 3D accelerator. That’s why we don’t compare the performance of Chaintech IMO-Desk I651U with that of other systems. We would like to offer you just a few tests. As for its main job, the IMO-Desk I651U is quite good at running multimedia applications.

When benchmarking Chaintech IMO-Desk I651U we installed an Intel Pentium 4 2.53GHz processor, 256MB of DDR333 SDRAM and a Western Digital WD400JB HDD into it. We also allocated 64MB of the system RAM for the needs of the graphics core.

PCMark04, PCMarks


PCMark04, CPU


PCMark04, Memory


PCMark04, Graphics


3DMark2001 SE, Default


Business Winstone 2004


Multimedia Content Creation Winstone 2004


Quake3, four, 1024x768x32, fps


Unreal Tournament 2003, dm-antalus, 1024x768x32, fps


Serious Sam 2, Grand Cathedral, 640x480x32, fps


No comments necessary. You can’t use Chaintech IMO-Desk I651U for running games of the current or even previous generation. At the same time, the system is quite fast at running applications that don’t use 3D graphics.


Well, one more manufacturer tried to get into the small form-factor PC business. Chaintech introduced its own unique vision of the home PC concept in the original IMO-Desk platform, which looks like a notebook, but is in fact closer to desktop systems. IMO-Desk I651U won’t bring you mobility, but instead it uses low-cost desktop components with better characteristics than their notebook counterparts. This computer can also be easily upgraded: you can replace the CPU, HDD or memory. Chaintech engineers must have read a lot in genetics: their hybrid of a desktop PC and a notebook is quite viable with many appealing features like small size and full integration.

The compact size and functionality of the IMO-Desk I651U allow using it not only at home, but also in office where its portability and compactness on your desk may come in handy.

As I have mentioned above, Chaintech prepares the whole family of such computers on different chipsets and for different processors, but as for this particular implementation of the IMO-Desk concept, the I651U model, it handles successfully such tasks as multimedia and office applications, Internet surfing and the like. Of course, there are some minor faults we have found and pointed out by IMO-Desk I651U. However, the very idea of the IMO-Desk seems excellent, and those deficiencies can be put up with.

In conclusion I would only like to add that the manufacturer plans to keep the price of the assembled system based on IMO-Desk I651U barebone below $1000, which is quite a nice start for a new platform like that, don’t you think so?