The ISK-300 is the first of a new series of mini-ITX cases from Antec. It is small, comes with an external adapter and internal DC/DC converter for power, and affordable. Is it a product that can be placed beside Antec’s best?
July 8, 2009 by Mike Chin
Antec ISK 300-65
Mini-ITX Desktop Case
When a case brand as big as Antec strikes out into a new sector, you have to sit up and pay attention. With a couple of notable exceptions, Antec’s bread and butter products are cases for ATX systems, especially for value conscious buyers still looking for quality. They tend to be sturdy, well featured designs without much bling, but high value with good quality compared to the competition. Antec cases are divided into several lines — Performance One, Sonata, Gaming, Skeleton, New Solution, Server and Rackmount.
The smallest cases Antec has offered thus far are the NSK1380, a large breadbox style case for mATX, and the MicroFusion Remote 350, a low profile mATX entertainment PC case. Neither of these are small by today’s Small Form Factor standards, not with diminutive products like the Asus Eee Box, Mac Mini or the Shuttle X27 out in the fray.
The ISK 300-65 is a major departure for Antec: It is a smalll mini-ITX case whose biggest dimension is just barely over a foot. Overall, it’s only about a third of the size of the Antec NSK1380, and about the same size and shape as the Shuttle X27 or Silverstone LC12. The ISK-300 eschews the traditional single-piece power supply, shipping with an external 65W AC/DC power adapter and a DC/DC power converter inside the case. The 65 at the end of the model number obviously refers to the power adapter. This is the logical design route for many mini PC systems, as the case can be kept small, and the heat associated with the PSU pushed mostly outside the case. The Silverstone LC12 took the same approach. Zotac anticipated mini-ITX power supply issues and packaged a 90W power adapter with its IONITX motherboard, with DC/DC conversion for lower voltages built right into the board itself.
The ISK 300 comes at an opportune time. DIY enthusiast interest in mini-ITX is greater now than ever before, with industry giant Intel producing modestly priced motherboards — some with embedded CPU and others with the 775 socket for use with a wide range of Intel CPUs. Most major motherboard makers have been producing mini-ITX boards for some time, but they haven’t been very aggressive about marketing.
Zotac, the new kid on the block, has really helped to change things (after the splashy entry by Intel) by producing a steady stream of mini-ITX boards aimed clearly at consumers. The problem is, retail cases for mini-ITX boards are few in number, and for the quiet seeker, most are downright poor. Most mini-ITX cases don’t seem to have any logical airflow design, the essence of efficient cooling, and so many use small fans that must run at high speed to accomplish any real cooling. There are few exceptions to this generalization, and it is an issue I have personally lamented since the very first mini-ITX board I reviewed many years ago. If the ISK 300 can provide the kind of quiet cooling performance larger Antec cases have developed a strong reputation for, then it will surely be welcome with open arms by many PC enthusiasts.
The ISK 300 looks similar in shape and size to the Shuttle X27 and Silverstone LC12.
Specifications & Features
|Power Supply||– 65-watt adapter + DC to ATX board|
|Drive bays||– External 1 x slim optical 5.25" bay|
– Internal 2 x 2.5" HDD bays
|Cooling system||– 1 side 80mm TriCool™ 3-speed exhaust fan|
|Front-mounted ports||– 2 x USB 2.0|
– 1 x eSATA
– Audio (AC’97 and HDA compatible) In and Out
|Expansion sot||– 1 half-height expansion slot|
|Construction||0.8mm cold rolled steel|
chassis for durability
|Compatible Motherboards||– Mini-ITX motherboard: 17 x 17cm|
|Case dimensions||– 96mm (H) X 222mm (W) X 328mm (D)|
– 3.8" (H) x 8.7" (W) x 12.9" (D)
|Net weight||– 7.4 lbs / 3.4 kg|
|Packaging dimensions||– 295mm (H) X 380mm (W) X 195mm (D)|
– 11.6" (H) x 15" (W) x 7.7" (D)
|Gross Weight||– 8.1 lbs / 3.7 kg|
Unlike most Antec cases, the ISK-300 ships in a plain brown cardboard carton. Not as useful for retail display, but less ink and industrial processing for glossy full color is definitely more eco-friendly.
ISK-300 is well protected with closed-cell foam in a brown cardboard carton.
Package contents include the case, a 65W external AC/DC power adapter, single-piece T-shaped vertical stand, some plastic zap straps for cable management, four small rubber feet with adhesive, and a package of mounting screws.
The cover is a U-shaped piece that fits like a clamshell over the bottom piece. This is a standard design for horizontal cases. The edges are folded over to hide sharp edges, and both the top and bottom halves of the case feel quite substantial due to the 0.8mm thick steel.
The fan is in a steel sub-frame that has an opening for another 80mm fan, blocked by a plastic plate that can be removed. The fan sub-frame requires just one screw on the back panel to be removed. Bayonent mounts secure it to the bottom panel.
Now that you’ve seen the internal layout, the airflow design of the case should be apparent. The narrower slot vent on the top of the cover is the main intake, and the outside air is forced across the motherboard and the CPU area before being evacuated out the side (or top, depending on how the case is positioned). Since there are no other vents, this is the only air flow path through the case. It’s a simple intelligent design that contrasts with many other mini-ITX cases: Some have inadequate vents for any kind of effective airflow and use fans that are far too small for quiet airflow, while others have too many vent openings, preventing any directed air flow over the hot spots.
Whether vertically or horizontally positioned, the airflow path remains the same: Intake via the rectagular slot on the wide panel of the cover, and exhaust through the 80x25mm fan.
TESTING & SYSTEM INSTALLATION
The obvious way to test a system like this is to install a system and check cooling and noise under idle and load conditions. But which mini-ITX board?
Initially, one of the Atom-embedded boards seemed best: Zotac IONITX embedded dual-core Atom board with nVidia chipset or the Intel D945GCLF single or dual core Atom board. However, on further reflection, neither seemed ideal. The Intel Atom boards come without a fan for the CPU, but the 945G chipset has a small fan on its heatsink, and it probably cannot be dispensed with either. In our testing, the Zotac IONITX board was cooled adequately without any fan on the open bench, so it seemed obvous that it could be cooled with just the single fan in the Antec case. This seemed too easy to accomplish. Our Zotac sample also came with a 12VDC input power connector, onboard DC/DC conversion for the multiple DC lines, and its own external AC power adapter. Using the Zotac board would not allow us to test out the integrated Antec power solution.
The Intel Atom boards’ CPU heatsink is tiny but well positioned for cooling by the Antec ISK-300’s single 80mm fan. However, the likelihood of effective NB cooling without that little fan seems low.
What about a full-fledged socket 775 board with a C2D processor? Our Intel E7200 sample has proven to be quite a power efficient processor in previous motherboard tests, and with the right heatsink, it might be cooled adequately with just the Antec ISK-300 case fan. The Zotac GeForce 9300-ITX WiFi we tested is a full-featured mini-ITX board with good layout and large NB heatsink. This seemed the most promising, even though the system would likely push the ISK-300 to its thermal limits and the integral power supply to its limits as well.
The CPU socket on the Zotac GeForce 9300-ITX WiFi is positioned nicely, very close to the Antec ISK-300 exhaust fan, though space is tight. The NB heatsink is big with nice spacing between fins for low airflow impedance.
The big challenge here was to find a heatsink that would fit yet have big enough cooling surface area (read: fins) to allow operation without a fan directly on the heatsink. The space between the top of the CPU and the bottom of the drive tray frame is approximately 6.5cm. Getting rid of the drive frame would give us just under 1cm extra height, which is still pretty short at 7.5cm.
A stock Intel heatsink measures about 6.3cm, so it would fit fine. No tower heatsinks need apply here; there are all too tall, even the Scythe Ninja Mini. Our favorite cooler for quick and easy testing around the lab, the Arctic Cooling Alpine
7 Pro, was also too tall at 8.3cm to fit. The Scythe Big Shuriken, a sample of which arrived in the middle of the testing for this review, seemed promising at first, but ended up being unusable because it was impossible to gain access to the mounting pushpins under the top fin stack when we attempted to mount it on the Zotac board.
POSTSCRIPT on Fitting the Big Shuriken, 16 July 2009
After this review was posted, some forum members noted that a promotional photo from Scythe showed the Big Shuriken mounted on a Zotac 9300-ITX board and wondered why SPCR could not replicate this. The following response from a Scythe contact clarifies this matter:
So if you’re willing to do this, I’d venture to say the BS will work fine on a system similar to our test setup here.
A few other heatsinks that look promising (in terms of fit and performance) but we didn’t have on hand:
In the end, we tried the stock and Apine 7 Pro coolers with the heatsink fan removed, and then the stock Intel cooler with the fan at very low speed.
We also decided to try a solid state drive in place of a 2.5" notebook drive. The reasoning was as follows:
The SSD on hand was an OCZ Vertex 30GB, the most affordable model from one of the most highly regarded SSD series on the market today.
Measurement and Analysis Tools
Primary Audio Test Tools
THE BUILD: TIGHT SPACING
Motherboard and drive installation was simple, but cable management was not. As mentioned earlier, the main cables from the back panel DC input to the DC/DC converter board are too short and run straight in front of the fan. The output cables, in contrast, are a bit too long; too bad they were not made modular. It’s difficult to find room to keep them tidy in the small case. The extension of the drive tray to the back of the case eats up room over the motherboard, which seems unnecessary. Given the low weight of a slim optical drive and two 2.5" drives, the two screws affixing the drive tray to the front of the chassis might be adequate. Putting the frame over the motherboard to the back of the chassis intrudes not only into the vertical space for the heatsink but also impedes access to connectors on the board. Installing a component into the expansion slot would have been a messy challenge.
Stock Fan Measurements
The stock fan is an Antec TriCool 80x25mm double ball bearing fan with seven blades and the now familar 3-position switch. The speed switch is attached via cable to the fan, and is held to the back of the case with two small screws. The geometry is not good: The blades’ trailing edges are nearly parallel to the three struts, which suggests that the noise generated will have high tonal aspects.
Stock Antec TriCool 80x25mm double ball bearing fan
The fan was measured while mounted in the Antec ISK-300 case with the cover on. The case was placed at the edge of a table in the anechoic chamber. Two sets of SPL measurements were performed, one at 1m as usual, and another at 0.6m, at the ISO 7779 (PC noise measurement standard) seated user position. The ISO 7779 seated user position SPL measurement will be conducted with PCs and cases that are likely to be placed on the desk near the monitor, as it is more relevant than the 1m distance usually used.
Stock Fan Measurements (Baseline Noise)
High – 5V
High – 4V
At all but the lowest speeds, the stock fan was not quiet. It had serious tonal elements at all speeds, even at the low setting. A kind of whispery high pitch sound underlay the normal wind turbulence noise, sounding at times like distant chirping of many crickets. It became very annoying over time. When manually undervolted, the fan speed could be reduced further for improvements in noise, but the airflow seemed too diminished to be useful. The minimum start voltage was 4V with the switch set on high.
The green arrows point to the tonal aspects of the sound with the fan set to low, measured from a meter away. The peak near 4kHz is probably the annoying whispery high pitched noise, which is present at virtually every fan speed, even as far as a couple meters away.
This frequency spectrum was captured with the microphone 0.6 meters away, a typical seated user distance. The fan was set to a very low speed, with 5V, speed switch on high. From a meter, it measured only 13.5 dBA. That ~4kHz peak persists here, and it’s plainly audible.
Could the acoustic performance of the fan be caused by bearing damaged in transit? Possibly but unlikely. There was no indication of any bearing damage that we could identify. It simply appears to be a fan of poor acoustic quality. It’s the only noise source in the case; why not spend a dollar or two more on a better fan when it’s so critical for overall acoustics?!
TEST RESULTS – continued
A. With Stock Case Fan: Intel Heatsink, fanless
The temperatures quickly soared to extreme levels. Amazingly, with the stock fan on low, the system did not crash when the CPU stabilized at 90°C. However, few users would be comfortable with the CPU running so hot. This setup does not provide good enough cooling.
Stock Case Fan + Intel Heatsink, fanless
With the case fan set to medium, CPU temperature improved a bit but it would still be considered too hot by most users. The noise level was also too high. It is clear that the stock Intel heatsink is not suitable for fanless cooling of the E7200 processor in this case. Perhaps not in any case.
Could we get better cooling at higher fan speed but with a quieter fan? How about a Noctua?
B. With Noctua 80mm fan: Intel Heatsink, fanless
Noctua fans are priced high and have a repulation for very good acoustics. The Noctua NF-R8 substituted for the stock Antec fan is rated for lower speed and noise than the Antec. It also comes with elastomer plugs for softmounting to prevent vibration from entering the case and causing extra noise.
Since variable control over the fan speed was wanted, when the TriCool fan was removed, the hole on the back panel for its 3-position switch was used to jury-rig a Zalman Fanmate 2 variable fan controller in place with a some double-sided sticky tape. The long cables of the Zalman controller made for an even bigger wiring challenge, but it all got stuffed away reasonably well.
Noctua NF-R8 mounted with soft plugs.
Noctua NF-R8 Fan Measurements
Stock Antec TriCool
High – 5V
At the lower speeds that we’re most interested in, the Noctua is several decibels quieter: At 1150rpm (equivalent to the LOW setting on the Antec fan), the Noctua is 3 dBA quieter from 1m, and 4 dBA quieter from closer up. The overall character of the Noctua’s noise is much less obtrusive. There is some tonal whine at higher speeds but at 1150rpm, it’s nice and smooth.
Would running this fan at 7V improve on the cooling performance compared to the stock fan on low? In a word, no. The noise level was much lower, but the temperatures remained unchanged. Increasing the fan speed to 9V gave better results, but still not really acceptable, and the noise level became too high anyway.
Noctua NF-R8 fan Case Fan + Intel Heatsink, fanless
TEST RESULTS – still continued
C. With Noctua 80mm fan: Arctic Cooling Alpine Pro heatsink, fan removed
It was time to try a different heatsink. This time, the Arctic Cooling Alpine
7 Pro was called into service. With the integral fan it stands too tall to fit, so the fan was removed. Load testing was done again. Alas, the results were only a couple of degree better than the with the fanless stock Intel cooler. Time to put a fan on the heatsink.
Noctua NF-R8 fan Case Fan + AC Alpine
7 Pro, fanless
D. With Noctua 80mm fan: Stock Intel Heatsink, fan at very low speed
Since it was about the only heatsink/fan on hand that would fit, a stock Intel socket 775 cooler was installed, with fan. It is a PWM fan, and the Zotac board has a PWM CPU fan header, so it was plugged into the board. The BIOS fan control was used to select the lowest fan speed. On this particular Intel heatsink/fan, that speed turned out to be 460rpm. It barely made any sound at this slow speed, but instinct suggested it would be enough to keep the CPU temperature under control.
Minor variant stock Intel heatsink/fan: The fan is frameless.
Noctua NF-R8 Case Fan + Intel stock cooler @ 460rpm
There were no obvious tonalities in the sound. Note the peak near 20kHz; this is from the power adapter, which was placed right next to the case on the desk. It may be audible to young people with excellent hearing. Simply placing the power adapter on the floor makes the sound immeasurable from the microphone position.
Finally, the component temperatures fell to a safe range. The noise level was quite modest. With the Noctua fan set at 5V, the overall noise was quiet enough at the seated user position to be acceptable over extended periods even for individuals with low noise tolerance.
E. With Two Noctua 80mm fan: Stock Intel Heatsink, fan at very low speed
It was the last thing left to try, in the absence of more suitable heatsinks, and deemed worth doing by the SPCR team of proofreaders and subeditors. Sigh. Installing the second fan with anti-vibration plugs was tricky and tedious due to the lack of space to pull the plugs through. In the end, only one pair of the plugs was used, on opposite corners. The other corners were damped and secured with some double-sided sticky foam tape. A Y-splitter was used to parallel-wire the second fan with the first to the Zalman Fanmate controller. That extra fan would pull up to another 1.32W which seemed small enough not to be an issue for the power supply.
Two Noctua fans in place. You can see the mess of wires on the left, including the Y-adapter. It still all fit not too badly though.
Two Noctua NF-R8 Fans + Intel Stock cooler @460rpm
So, as expected, the increased airflow of two fans lead to lower temperatures all around. The drop in GPU temperature was nearly 20°C, which suggests that the second fan may have changed the airflow path across the motherboard and exposed the NB chip heatsink to greater airflow. The maximum AC power of the system also dropped by 3W, which suggests higher efficiency of power components (VRMs on the motherboard as well as the DC/DC converter) due to improved cooling.
The cost in noise at the 0.6m seated user psotion was about 4 dBA, from 17 dBA to 21 dBA. Subjectively, it was still unobtrusive and very quiet, though no one could say it’s inaudible. Putting the unit behind the monitor brought the noise down to 17 dBA again. This would be a useful strategy for those seeking minimal noise from any small desktop computer.
Upon request, Antec provided detailed specifications of the power adapter and the DC/DC board used in the ISK-300. The power adapter is made by Delta Electronics, who has been working with Antec on other power supply products in the past year or so. Curiously, the DC/DC converter turns out to be made by the ODM (original design manufacturing) Product Division of Gigabyte. The most salient specs of the two power components are summarized below.
Antec ISK 300-65 AC/DC power adapter Specs
|Input||90 ~ 264VAC, 50/60Hz|
1.5A Max at 65W load, 100VAC input
|Output||19V (18.4~ 20V), 3.42A|
|Efficiency||More than 85% average efficiency of 25%, 50%, 75% and 100% load at 115/230 VAC, measured at the end of DC cable.|
|Output Ripple & Noise||<350 mV peak to peak (tested at 25° C).|
|Protection||Over Voltage, Over Current, Short Circuit, Over Temperature|
|Temperature||Operating range: 0 to +40° C|
Case Temp. Rise: 45° C at 40° C Ambient
Antec ISK 300-65 DC/DC Converter Specs
|Input||19V, 65W max.|
|Output||5V/ 7A Max.|
5V_SB/ 1A Max.
-12V/ 0.1A Max.
During thermal/load testing, the AC power consumption at full load started at 60W and increased slowly to a maximum of 66W. With the coolest configuration tested, the maximum power dropped slightly to 63W. This shows that the motherboard VRM and/or the DC/DC converter efficiency drops as they get hotter. It may also be the case that both were red-lined by the system’s power demand when the system was not cooled adequately. The second fan caused no clearly measurable increase in power; the increase was probably within the margin of error of the power meter (under 1W).
At idle, power draw was 30W, which is quite low, and it suggests very high efficiency, very close to the picoPSU with 80W or 110W power brick. In previous testing, same motherboard and components drew 35W at idle and 65W at full load with a 400W 80+ Seasonic power supply.
During full load testing, the power brick became quite warm, but never too hot to touch. The brick would likely get hotter with higher ambient room temperature than in our lab, where it never rises above ~25° C. The DC/DC board temperature was not checked. These devices typically have >90% efficiency, so what little heat it produces would be far less than any of the other parts within the case, namely the CPU and the motherboard components.
When the computer was turned on and working, the power brick emitted a low level of ultra high frequency noise (near 20kHz) which should not bother any people. It’s too low at level and too high a frequency. We cannot comment what effect it might have on dogs and bats.
When the computer was turned off or put in standby mode with the power adapter still plugged in, the buzzing noise moved down in frequency to the midband and became much more audible. It could be just heard a meter away. While this can be disturbing, it’s quite common with power bricks. Most of the time, such noise is not heard because power bricks are usually stuffed behind a desk or other other furniture, usually on the floor.
1. The system is quieter, subjectively, when placed vertically on the stand than when set horizontally on its rubber feet. In the latter position, there is greater mechanical coupling between the case and the table, leading to a slightly higher level of hum. This was difficult to measure, but fairly easy to hear.
2. The HDD activity LED connector spans 3 pins. Our test motherboard’s HDD LED pins are next to each other, however, so it was not used. It’s a simple fix; just cut the connector in two or remove one of the wires from the connector, and move it next to the other wire.
3. If more room over the motherboard is desired, it’s possible to remove the back end of the HDD tray frame by popping out two rivets. Two screws still hold the tray to the front of the chassis, and this is probably enough to keep the tray stable even with a slim optical drive and a 2.5" drive. No guarantee — we did not try it.
4. The CPU used in our test setup is rated for 65W TDP, which is the same for all Intel dual core C2D processors today. We would probably have obtained better cooling results with a 45W TDP AMD dual-core, but a suitable AMD mini-ITX board was not on hand. There’s little question that the Zotac IONITX with dual-core Atom 330 processor would be easily cooled in the system, especially with a fan directly on that board’s heatsink.
5. Finally, we still think a more ideal heatsink — one that occupies the entire space and height available with large fins surface area not too tightly spaced — would allow good cooling of the components with just one quiet 80mm case fan.
These recordings were made with a high resolution, lab quality, digital recording
system inside SPCR’s own 11 dBA ambient anechoic chamber, then converted to
LAME 128kbps encoded MP3s. We’ve listened long and hard to ensure there is no
audible degradation from the original WAV files to these MP3s. They represent
a quick snapshot of what we heard during the review.
Each recording starts with about 6~10 seconds of the ambient in the anechoic chamber (silence), then 10 second segments of product
at various states. For the most realistic results,
set the volume so that the starting ambient level is just barely audible, then
don’t change the volume setting again while comparing all the sound files.
Comparable System sound files:
Antec’s first mini-ITX case is a solid if not flawless entry into a sector that is new to the brand. The overall airflow design in the case is sensible, simple and effective. It is better than any other case of similar size we know of. The build quality is good, with sturdy, heavy weight steel used everywhere except on the plastic front facia. The accessories include a nice one-piece vertical stand more stable than the common two-piece jobs. Styling is subdued and not quite as polished as Antec’s best conventional case offerings, especially the optical drive cover, but it all works fine.
Inside, the HDD mounting frame seems unnecessarily large. It extends over the motherboard and heatsink area, constricting the already tight space. Some of the power output cables seem a bit too long, while one interferes by running in front of the exhaust fan.
Another quibble is the 65W power adapter, which seems underpowered, even if the target motherboards are only low power embedded CPU types. An 80W or 90W adapter would provide greater headroom and flexibility for a wider variety of components. Despite reservations, our test system of a 65W TDP Intel C2D CPU ran without issues.
Our single biggest complaint is about the fan. It has a nasty sonic signature. This is not to say there are not worse fans. There are plenty of fans that sound worse. But as a big case brand, Antec can pick and choose from dozens of fan makers, and hundreds of fans. A better quality fan would cost very little more to implement; why was it not done? Silverstone, a brand not known in the past for quiet cases or fans, has made dramatic improvements in the sonic quality of its fans in cases we reviewed recently. If Silverstone can do it, surely Antec can as well.
Still, the fan is not a deal-breaker. It can be replaced easily, a better fan can be had for under $10, and many SPCR regulars probably have a spare quiet fan that can be pressed into service. The ISK-300 has far better potential for quiet cooling than others of similar size we know of. (Excluding the fanless heatsink cases such as mCubed HFX Micro or Coolermaster TC100.) For that reason alone, it’s welcome to the mini-ITX party. The option to add a second fan is obviously handy for users who seek quiet cooling for higher power components; two slow spinning fans often move more air while being as quiet or quieter than a single one spinning at higher speed.
A final attraction is that the price has been kept reasonable. Although the MRSP is $89, the ISK-300 is selling widely online today for under $70. Considering the inclusion of the silent and highly efficient power supply, it’s a pretty good deal. ISK is a new case series from Antec, and the 300 is a good first model. Hopefully, it is a harbinger of even better things to come.
Antec ISK 300-65 Case Balance Sheet
– Sturdy and small
– Good airflow design
– Built in fanless power supply
– Already set up for 2.5" drives
– Better cooling than other m-ITX cases
– Could be more attractive
– Lousy fan
– Could be a bit smaller
– AC/DC power adapter is only 65W
– No HDD soft grommets
Our thanks to Antec
Inc. for the ISK-300 sample.
Recommended by SPCR
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Zotac GeForce 9300-ITX WiFi
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