ugh. I think some of you are miss-directing your debating energy. We are talking about a test done by Tom's Hardware. If you think something was not right, you are welcome to point the error. And please do cause I tried and couldn't ... and since I have over $10K invested in audio, I am not particularly happy to hear that kind of stuff.
On short about the few possible errors pointed above:
There was no "amp issue" because because they compared complete DAC+amp packages: as provided by some MB, a complete o2/odac and a benchmark DAC with HP output. And yes a MB soundchip is basically a DAC ... and
here are some measurements for the latest/best such chips. Pretty good if you ask me. And
here is another similar test, posted right here on headfi.
The 99% refers to the population at large. No, I do not have any studies/numbers, it's just an approx based on my exp and some extrapolation: e.g. go on the street and ask people, see if more than 1% know what a DAC even is... or another sample, there are many billions of people which live with less that $1 a day. Generally, hifi as a whole is a 1% game ... or even less. And not sure why would anyone want to debate that.
I haven't read the test you're talking about - but I do have some general comments on the comments about it..... based on my experience with "computer sound cards" and "motherboard sound chips / implementations".....
If you look at the specifications on some (even relatively cheap) computer sound cards, they actually do seem to be quite respectable. However, in many cases, the actual performance you get seems to be not nearly as good as the numbers would lead you to expect. The last time I tried to make an actual recording (of a vinyl album) using a sound card that claimed "S/N of 96 dB", I was barely able to actually achieve a noise floor equal to the output of my phono preamp (since this was a sub-$100 phono preamp, which only claimed a S/N of around 70 dB, the sound card should have been a lot quieter and cleaner than it was). Honestly, the problems seemed to be related to the computer's having a poor ground (grounding things very carefully helped a little), and a very noisy power supply, and probably even the computer radiating enough noise into the room to cause some airborn interference with the phono preamp. This may suggest that "it wasn't the sound card's fault since the computer is a truly lousy environment for a sensitive audio component to be installed in", but the bottom line was that, with that sound card in the computer and connected to other equipment, I was totally unable to get even reasonably good performance.
Likewise, while the output specs on some sound cards (again even some reasonably cheap ones) suggest that many of them
SHOULD sound quite decent, or even "audibly perfect", it's been my experience that none of them actually do manage to deliver good sound quality without bleed through from the screen image into the noise floor, and without unacceptable noise levels in general. Over the years I've had several HP and Dell desktop machines, several Dell, Gateway, and Asus laptops, and a few custom no-name units as well, some with stock MB sound cards, and some with mid-priced add-on cards, and none of them was able to deliver audio performance that wasn't "audibly limited" when compared to even the sound quality of a $59 external DAC. (Since a sound card relies on the computer for its ground and power, and internal sound cards also have to deal with proximity to a massive amount of radiated noise as well, I don't see this as at all surprising. Note that, since grounding seems to be a large part of the issue, plugging headphones directly into the computer is more likely to produce better results than connecting the output to a stereo system or outboard headphone amp because, with headphones, the computer is acting as a "floating" device - and so noise between it's ground and true ground is mostly irrelevant.
I'm not suggesting that some computers may not have reasonably good sounding "sound systems" - at least under some conditions - however, for me at least, there are just too many variables, and too many opportunities for that not to be the case, for me to even consider using "the internal sound system in the computer" for "anything serious". (Since I have several computers, and lots of other equipment, I simply can't fuss a lot every time I hook up a different one in order to try and squeeze adequate performance out of a particular combination of components. I would really rather have a DAC that "I can trust to work with all my computers".)