Testing Methodology, Revised

For those of you who aren't familiar or don't remember, here's a brief primer on how we used to test cases to get you up to speed.

Acoustic testing is standardized at one foot from the front of the case, using the Extech SL10 with an ambient noise floor of ~32dB. For reference, that's what my silent apartment measures with nothing running, testing acoustics in the dead of night (usually between 1am and 3am). A lot of us sit about a foot away from our computers, so this should be a fairly accurate representation of the kind of noise the case generates, and it's close enough to get noise levels that should register above ambient.

Thermal testing is run with the computer having idled at the desktop for fifteen minutes, and again with the computer running both Furmark (where applicable) and Prime95 (less one thread when a GPU is being used) for fifteen minutes. I've found that leaving one thread open in Prime95 allows the processor to heat up enough while making sure Furmark isn't CPU-limited. We're using the thermal diodes included with the hardware to keep everything standardized, and ambient testing temperature is always between 71F and 74F. Processor temperatures reported are the average of the CPU cores.

That all seems fairly reasonable, but over time subtle issues have crept in that we're taking the opportunity to correct.

For starters, we've found that while the Extech SL10 is perfectly fine for testing sound levels at about 37dBA and up, it's downright lousy for handling anything designed for silent running. The meter only has an official noise floor of 40dB, which is frankly a bit loud. To produce more accurate results, we've switched over to a beefier Extech SL130. The SL130 is rated to go as low as 30dB (basically the lowest any reasonably priced sound meter will go). In addition, I've actually moved since I started doing case reviews, and my new apartment is much quieter than the old one, resulting in an ambient noise floor well below 30dB. Unlike the SL10, the SL130 won't make "an educated guess" about sound levels below its rated floor, either. I'm continuing to test acoustics with the microphone a foot directly in front of the top of the enclosure to ensure consistent readings on that front. Anything below 30dB still rates as "near silent", but this is a big step away from 40dB.

Meanwhile, thermal testing has proven to be a bit trickier than initially anticipated. Maintaining a consistent interior temperature of an apartment (or even just one room) is easier said than done. Even a variation in ambient temperatures that I mentioned before can color results. As a result, instead of using the absolute temperatures reported from the hardware's thermal diodes during testing, I'm reporting the delta over ambient temperature. Ambient temperature is also measured at the beginning of each test cycle (after fifteen minutes of idle, and before fifteen minutes of burn-in.)

Test cycles are also being ever so slightly modified. I'm continuing to use seven threads of Prime95 to stress the processor, but GPU stress is now being handled by eVGA's OC Scanner instead of Furmark. Furmark is an odd duck that I've found to be unreliable as a GPU stress testing tool; Furmark just consumes power, but doesn't actually simulate proper GPU stress the way something like OC Scanner will. We've also seen some driver tweaks by both AMD and NVIDIA over the years designed to prevent Furmark, so it's best to use something else.

As before, I'm continuing to use the thermal diodes of the internal components rather than separate thermal sensors, and CPU temperature is reported as an average of the four cores. SSD temperature will continue to be included as a representative of how well the enclosure cools installed drives, but chipset and RAM temperatures are no longer going to be included. RAM thermals are really only relevant in extreme cases, and modern chipsets just aren't the heat generators that old dogs like the X58 were.

One new wrinkle I'm including is fan speed, though. Since the CPU and GPU fans are both thermally controlled, it may be useful to see just how hard these fans have to work in any given enclosure. These results aren't going to be strictly comparable between enclosures due to variations in ambient temperatures, but should be a reasonable starting point.

Testing Hardware (Mini-ITX), Revised Conclusion: More Reliable Comparisons
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  • irow - Thursday, March 29, 2012 - link

    Why not forget about motherboard/cpu/gpu etc and just put a sound source (speaker) and a heat source (eg light bulbs) inside the middle of a case and measure outside volume and internal/external fan vent temperatures ?? Although you may have to change a few bulbs, you could use that system for years while different components come and go. Reply
  • dac7nco - Thursday, March 29, 2012 - link

    Article: "I've actually moved since I started doing case reviews, and my new apartment is much quieter than the old one, resulting in an ambient noise floor well below 30dB."

    Isn't Anandtech in North Carolina, in an office complex? I have always thought you guys had your own (professional) facilities. I wouldn't bench hardware that could potentially cost a company millions (in lost sales) in a spare bedroom. Enthusiast hardware I understand; overclocking GPUs and CPUs is meant to be at home... but sound testing?

    Daimon
    Reply
  • LeftSide - Friday, March 30, 2012 - link

    Lightbulbs are a bad idea because they transfer heat via radiation. It would heat the metal on the side of the case and not be an accurate representation of computer hardware. Cases are very different placing components and fans in different locations. The only accurate way to test is to use actual hardware. That way you can test and measure hard drive temperature, video card temperature, and cpu temperature separately.
    I'm afraid the speaker idea would not work as well. Having 4 fans in one case and 2 in another would have different sound properties than a speaker in the center of the case.
    Reply
  • mariush - Friday, March 30, 2012 - link

    It might be a better idea to use a 500-600w gold power supply for the mini-itx systems, perhaps even one semi-passive one (as in one that turns off fan at lower power consumption).

    Gold efficiency power supplies at that wattage are cheap enough these days and lots of people build such small systems to watch tv so they don't want lots of noise.

    At the same time, the reduced air circulation inside (if the power supply won't spin its fan) would introduce some interesting effects and provide some good data about how well the air circulates inside the case and how well the case will work in time (people don't clean their cases often so they can get dusted, blocking vents)
    Reply
  • Death666Angel - Friday, March 30, 2012 - link

    "instead of stratifying between ATX and Micro-ATX/Mini-ITX, it makes more sense now to stratify ITX as a separate platform"
    Been waiting for that for a while! My last 2 enclosures were mATX (one cube and the TJ08-E) and both are pretty powerful. There is no difference between mATX and ATX as long as 2 graphics cards or 1 graphics card and 2 other pci(e) cards are used and not more.
    Reply
  • hpzSZo95 - Friday, March 30, 2012 - link

    Almost all builds will include a physical hard drive, not just an SSD. I think it is important to include a 3.5" 7200 RPM hard drive in the test bed as a physical drive: 1) generates heat (small amount), 2) can block airflow (many cases mount these in front of the front intake fans), 3) generate noise, especially vibrations if mounting is insufficient.

    Also, when reviewing a case the ease of assembling the system should be considered. I recently added an SSD to an existing system, which should be fairly simple from an assembly point of view. Unfortunately my 3 year old case has only 3 internal 3.5 bays in a single drive cage, which are occupied by a 3 disk RAID, and no 2.5" drive. It also has 2 3.5 external bays. I had to use an adapter to mount the 2.5 drive in the external bay behind a face plate. This required removing the GPU and memory as the tall heat spreaders blocked the installation.

    My point is that while I doubt adding a single 3.5" drive to any modern case will cause issue, each additional component does increase the risk of complicating the assembly, so typical components should be included.
    Reply
  • shin0bi272 - Monday, April 02, 2012 - link

    I agree. My friend just built a system and he planned on using his old 7200rpm drive but his other friend that he had put it together said the drive was bad... he didnt splurge on an ssd he went out and bought another hard drive. Plus with gaming you wont see any FPS increase with an ssd so the only benefit you'll get is load times. Reply
  • Shinobisan - Friday, March 30, 2012 - link

    I notice you're using a Corsair Link in the new test bed... Where exactly did you get one?
    I can't find them anywhere for sale (at least online... I'm in the middle of no-where).
    I've asked Corsair themselves a gob of times, and only received abject silence.

    I was really starting to think they were vapor-wear. !

    What is the source? ? ?
    Reply
  • Shinobisan - Friday, March 30, 2012 - link

    Ah... page 2 says you got it directly from Corsair... so... still vapor wear. :( :(
    (shinobisan = pouting)
    Reply
  • Luay - Sunday, April 01, 2012 - link

    Sticking with the small CM 212 Hyper Evo for all case reviews will mislead you and the readers whne it comes to CPU thermals.

    The cooler is great for narrow cases such as the Antec 300, Rosewill Blackhawk and such, but for the wide full towers it is less effective and a much larger cooler is required to suck in cool air from the top, so that might be unfair to the larger cases when you review their CPU thermals.
    Reply

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