25 Kilograms of Silence: Zalman TNN500A Case Review

Today we would like to introduce to you a really unique product: Zalman PC case, which is none other but twenty-five kilograms of aluminum, heat pipes, electronics and wires and no fans! Want to learn more about this extraordinary solution, read our new review now!

by Tim Tscheblockov
08/18/2004 | 08:16 PM

I guess I don’t have to introduce Zalman to you – the company is a renowned manufacturer of effective low-noise or completely noiseless cooling systems for CPUs, graphics cards and other PC components. Zalman’s unique CPU coolers are a kind of golden mean – they are the quietest among the most efficient coolers, and the most efficient among the noiseless ones.


Well, you could argue that issue, while the subject of my today’s review is an unarguably unique product. I am speaking about the Zalman TNN500A, a system case for an absolutely silent computer

Here it is: twenty-five kilograms of aluminum, heat pipes, electronics and wires and no fans. Twenty-five kilograms of pure silence!

Closer look: Exterior

The TNN500A looks as solid as a computer case might possibly look. Well, it doesn’t even look like a computer case, but rather like an industrial machine whose exterior is dictated by functionality, not cute looks. Every centimeter of the TNN500A seems to be saying, “This thing is made for hard labor, not to please your eyes”.

The sides of the monster are aluminum panels with vertical ribs. These panels take the most amount of heat generated by the PC components, and their ribs ensure a more efficient transfer of heat to the outside air as the passive cooling concept implies. The top and bottom of the TNN500A are slabs with vent holes:

The top slab has handles to carry the system about; the bottom stands on four wheels of a special design. To steady the computer, you unfold rubber legs at the bottom, which lift the case above the ground.

The face and rear panels of the system are made of aluminum and are fastened to the case in – you can open them as you open a door. The front of the case only has the Zalman logotype and a porthole for a light pipe that transmits the light from the power-on and HDD activity indicators. The rear panel has no openings at all:

The system controls are all located behind the face panel. You open it up to see USB ports, power-on and reset buttons, HDD activity and power-on LEDs, and a highlighting-on button. The simple black panels with buttons are fastened to the side of the case from the inside – they are another reminder: functionality comes first, “niceties” later.

A zigzag construction is visible at the bottom. According to Zalman, it intercepts electro-magnetic interference from the system components. You find these “volutes” at the top and bottom slabs of the case. By the way, various cables – to attach the mouse, keyboard, monitor, power and so on – can be output through them when the rear panel is shut. The drives section can only be accessed when the face panel is open, of course:

With the highlighting turned on, the insides of the system are lit with two rows of LEDs – that’s beautiful, but only visible when the face panel is open:

So, the Zalman TNN500A looks like a huge passive heatsink that ended up as a PC case due to the vagaries of life. I don’t say that it looks ugly! On the contrary, its Spartan, “industrial” design makes it very impressive.

Now let’s take a look inside

Closer look: Inside the Case

To get into the TNN500A, you open the front and rear panels, unscrew two rows of big screws that fasten the side panel to the top and bottom slabs and unfold the case as you do a book: unfastened, the side panel can rotate on its hinges:

The left panel carries a PSU and aluminum ledges for installing hard disks and optical drives:

The heat generated by an installed hard disk drive, for example, will be transferred to the ribbed side panel via this ledge.

The flat PSU is just spread along the inside of the side panel. Its design is most unusual as all its elements have a low profile. The big and flat high-voltage electrolytic capacitors catch the eye in the first place:

A large plate, smeared with thermal paste, is fastened to two bars that take heat off the switch transistors and diodes:

This side-view snapshot shows you that the power transformer also contacts the plate:

The plate, in its turn, gives heat out to the side panel of the case. For better heat exchange, they use thermal paste:

Other PSU components, which don’t generate too much heat, are cooled with air that comes through the vent holes in the PSU’s cover. The characteristics of the unit can be read from its casing:

This PSU is a most curious device. It is called ZM-350, but its total wattage on all the power rails is 300W. However, the maximum currents on the power rails don’t comply with the specification of 250W units even! The maximum current on the +12v rail is recommended to be 13amp for 250W PSUs, while the ZM-350 can only supply up to 12amp. What’s most strange, “ordinary” PSUs from Zalman are much more honest: for example, the 300W ZM300B model provides up to 18amp on the +12v rail instead of the recommended 15 amperes.

The Zalman TNN500A permits installation of an optionally purchased and more powerful PSU – its landing place is marked on the side panel. Compared to the ZM-350, that PSU takes more space. If you prefer to leave the standard PSU, you should be very careful when assembling a system: a powerful graphics card needs 3-5amp on the 12v line; a top-end processor requires 5-7amp more; and the hard and optical drives take 1-2amp. Thus, it is very simple to reach the maximum of 12amp, and the PSU will be working under very harsh conditions.

Let’s move on. The central processor and the graphics processor – the hottest components of any system – are cooled with heat pipes. The CPU, as the main heat source in the system, has as many as six heat pipes:

With one end, the pipes go into a special unit that contacts the CPU. With their other end, the pipes fit into the aluminum “landing grounds” that transfer heat to the side panel of the case. The CPU unit is a massive contraption consisting of two parts: one, all-copper with golden coating, transfers heat from the CPU to the heat pipes; the other, aluminum, is placed on top and is fastened with heavy screws for a tight contact between the pipes and the copper part:

The surface of the copper unit is smooth, but not ideally flat, as you can see in the photo:

Zalman claims this system can digest up to 150 watts of heat. This is evidently enough for all the modern processors. Note that the set of heat pipes that you receive with the TNN500A and see in my pictures suits only those mainboards that have the CPU socket near their edge. For mainboards with the CPU socket shifted to the center, i.e. farther from the “landing grounds” of the heat pipes on the side panel, you have to use longer pipes. These longer pipes are purchased separately.

The GPU is cooled down with heat pipes, too. With one end, these pipes contact the GPU unit, with another – the side panel of the case, using the same aluminum fastenings as the CPU heat pipes do:

The GPU cooling system is capable of removing up to 50 watts of heat, and that’s enough even for the new-generation cards. However, Zalman recommends using another set of pipes with graphics cards more powerful than the RADEON 9700 and GeForce FX 5700. Such pipes are fastened to the side panels with their ends and to the GPU unit with their middle. You may have guessed that such pipe-work is purchased separately, too.

Special aluminum plates are fastened to the top slab of the case – you can accommodate two optical drives on them. Lower, there’s a special cooling basket for the hard disk drive:

This basket contacts with the sides of the hard disk, and the row of heat pipes, inserted into the sides of the basket, must facilitate heat transfer to the air inside the case. The basket is fastened to the panels with four stiff rubber bushes – you can see one in the snapshot.

So, the TNN500A, unlike a decent computer, does not have a single fan. Heat is taken off the system components by means of heat pipes, or air, or through direct contact (through the mounting plate and the side panel). So, the only noise sources of such a system will be hard and optical drives – they have moving parts. Well, even the drives will be more quiet in the TNN500A than in ordinary cases – the drives installed on the ledges attached to the side panel of the case produce much less vibration and noise due to the stiff fastening and the huge mass of the case that absorbs vibration. The drive installed into the cooling basket is less noisy because of the stiff hanger. For the system to be even more silent, Zalman quite expectedly recommends that you use hard disk drives with fluid dynamic bearings.

Now that we are done with the internal inspection, I am going to try to assemble a system in the TNN500A.

Assembly Tips and Tricks

Judging by the bruised looks of our TNN500A, it came to our test lab after a series of long and difficult trials, also having been used as a bobsled at the last Olympics. However, those people who performed those tests were not smart enough to slap some thermal paste on the places where the heat pipes are fastened to the side panels, as the instruction and common sense both suggest. So, I first had to unscrew the fastenings of the heat pipes and apply some paste:

Before installing the pipes back, I put some thermal paste into the grooves of the fastenings, too:

Having installed the mainboard, CPU and the CPU cooling system, you can proceed to installing the graphics card. I used an inexpensive graphics card from ASUS based on the NVIDIA GeForce FX 5200 GPU:

First, you remove the standard cooling system altogether and replace it with the GPU unit:

The Zalman TNN500A comes with two such units: the longer is for ordinary GPUs and the shorter is for GPUs whose protective frame protrudes above the die surface. The snapshot below shows you the bases of these units with the fastening brackets, which can be moved and rotated for an easy installation on any graphics card.

A GeForce FX 5200 graphics card didn’t die during the installation into the Zalman TNN500A, although got very close to that at moments. You know, it takes quite an effort to put the graphics card into this system case. It is practically impossible to insert the card into the AGP slot and lay its bracket on the vertical aluminum bar that holds down expansion cards without applying brute force. I could only install the card easily, like in an ordinary case, after I unscrewed that bar and put it back only after the card was in its slot.

Getting some experience with graphics card installation, I went for a risk and, against Zalman’s recommendations, installed a powerful card from PowerColor based on a new-generation graphics processor, the RADEON X800 Pro from ATI Technologies.

I used the short fastening unit for that graphics card:

I had no problems installing it onto the RADEON X800 Pro:

I will try to prove Zalman’s claims that the GPU cooling system can handle up to 50W of heat. Power consumption and heat dissipation of the RADEON X800 Pro are similar to that value (according to this article called Power Consumption of Contemporary Graphics Accelerators. Part I: Graphics Cards on ATI Chips).

The optical and hard disk drives fit into their designated places with ease:

I put a floppy drive and a second HDD on the side ledges:

The ledges on the side panel are universal – you can put a hard disk drive there…

…or a floppy-drive:

So, everyone’s accommodated. After I attached all the power and interface cables, the assembled system looked like that:

On the snapshot of the system made from behind, you can see the ill-fated vertical bar that the graphics card and other expansion cards are fastened to. The connectors of the mainboard press against the I/O shield, an accessory to the mainboard:

The system is complete. Let’s test it!

Testbed and Methods

To check out the efficiency of the Zalman TNN500A, I assembled in it a system of the following components:

I performed my tests in several operational modes:

I took down the temperatures after half an hour of the system working in each of the modes. The CPU temperature was monitored with the help of Motherboard Monitor of the latest version; the temperatures of the GPU and the graphics card’s PCB were read by RivaTuner; the HDD temperature was reported by DTemp.

The room temperature, the air temperature inside the case and the temperature of the graphics memory chips was measured with a Fluke-54 II thermometer.

I had no desire to lose a good hard disk drive in case the test went awry, and I only found one drive with support of S.M.A.R.T. and temperature monitoring, which could be sacrificed. So, I performed each of the tests twice: the first time I put down the temperatures of the system components and the hard drive when it was installed into the “cooling basket”, and the second time I put the drive on the ledge of the side panel and only measured the temperature of that drive.


So, here are the results of the tests:

Let’s go through the components one by one. The CPU’s 45-46°C in the Idle mode and 63°C under a load is an excellent result for a processor overclocked to 3.6GHz and cooled by an absolutely noiseless cooling system. The Zalman TNN500A gets the maximum possible score in this item.

The temperatures of the GPU and the graphics memory are 50-51°C in the Idle mode and 77-78°C under a load. This is not a catastrophe, but still very hot. For example, with the standard cooling system, the RADEON X800 Pro was 60-65°C hot under a load (see our article called PowerColor RADEON X800 PRO Graphics Card: Modification, Extreme Overclocking and a Duel against Leadtek GeForce 6800 GT).

So, while the Zalman TNN500A handles the RADEON X800 more or less successfully, I wouldn’t dare to install a more powerful graphics card into it.

The TNN500A has a serious chronic defect in its graphics card section: heat pipes only transfer heat off the GPU, while many graphics cards have hot memory chips that require active cooling at least. But installing a fan to blow at the memory chips on the graphics card means losing the main property of the TNN500A – its absolute noiselessness.

The temperature of the hard disk in the “cooling basket” with heat pipes was 44°C in the Idle mode and 57°C after half an hour of defragmentation. This is not just “too much”, that’s close to a catastrophe! I wonder what the temperature of a faster and higher-capacity drive is going to be here, if the old DTLA came under a threat of overheat. Obviously, the heat pipes are not efficient here, and quite naturally: there’s no fan to blow at them, and air circulates very slowly inside the case, mostly due to convection.

The situation changed dramatically as soon as I installed the drive onto the ledge of the side panel: 38°C Idle temperature and 44°C Burn temperature! Heat generated by the drive is immediately handed over to the side panel through that ledge and the thermal condition of the device gives no cause for concern. Installation of several hard disk drives on the ledges of the side panel doesn’t provoke any worsening of the thermal situation: the devices won’t heat each other up, but will give all their heat to the side panel immediately.


So, what are the winning aspects of the TNN500A system case from Zalman? I think they are the following:

The disadvantages of the TNN500 may outnumber its advantages, though: