No, they won't help airflow.
Just another piece of windowdressing to get you parted with your money, they sold thousands of blue orbs too, before people got smart, guess rounded cables are outlasting even that.
If they helped in my system, it was fairly limited. However, if you only have a small amount of airflow to start with (e.g., you're designing a case for a minimal use of fans to be quiet), it might make a 1-2C difference, absolutely tops.
The thing I found round cables more useful for (I had at most a modest 1C drop) was that you could much more easily route the cables and get them out of your way when doing other work.
But I think that the general consensus is on -- the round cables make at best a small difference, unless maybe you have little airflow to start with, and are generally more for aesthetics.
Ive got a pair of ATA-133 cables, a 2 device SCSI-2 cable and a floppy cable from www.theoverclockingstore.com , and theyve all been fine...dont help airflow one bit, but they work and theyre a whole lot neater than flat ribbon cables
Also, we use both flat and round ribbon cable at work (I work in elctronics/engineering, we manufacture switching and control equipment for the mining industry) and we only really use the flat stuff for short cable runs..we always use the round stuff for longer runs, mainly because its just so much easier to route and looks tidier. Crosstalks not a problem with it, not at such a low voltage anyway (it very rarely carries any more than 12v), and I wouldnt have thought the signal from a mobo to a h/drive would be carrying much more than that.
It's not the voltage, it's the frequency that causes cross-talk. The frequency is what's causing the magnetic waves to propogate from the wire into other wires. The faster the drives get, the more problems will arise.
How many people right now are crying because XP keeps throttling back the DMA settings on their drives everytime it encounters 6 or more data errors.... well Duh. Not enough to kill your data, or corrupt your drive, but how's their benchies now with DMA set back to PIO mode? I'm busting past 50MB/s read times.
Your better of paying for longer cables so you can fold them neatly out of the way. You wont have as much problem with cross talk folding as you would with any round cable. And you can make it look neater and get better air flow with well folded cables.
I read the article. It seems to me that the bigger issue addressed in that article, in part, is the length of the cable. After anything much larger than 18", the signal attenuates to the point that its strength is comparable to or dominated by the noise of the signal.
When I researched fiber optics and mode coupling (read cross-talk), the mode-coupling occured when the EM fields interracted at too close a range and shared a proper combination of modes and frequencies. However, sufficient distance between the signals generally prevented all but nominal cross-talk. This was usually done in the form of a jacket around the cladding of the fiber, or if the field was well-confined to the core, a sufficiently thick cladding will do. (A fiber is generally three layers in telecom: core of silicon glass with highest refractive index, surrounded by a cladding of silicon glass with lower refractive index, followed by a jacket which is by and large opaque to the EM you are transmitting.)
With the 80-PIN IDE cable with interspersed, interlaced ground wires, I think the concept is similar. The distance of the ground wire between two "adjacent" signal wires allows for a decent amount of attenuation of the fields for minimal interaction. Also, the interlaced grounds basically allow the induced signals from the fields to cancel one another out to some extent. (Forgive me if I make a mistake here -- my experience is with fiber-optic mode coupling and fiber Bragg grating research, not with EM signals through copper wires.)
I think with the better-made rounded cables, the interlaced grounds still fulfil their roles, especially in providing some separation between the signal wires and allowing the impedences to cancel. If the wires were extremely tightly bundled, with separations comparable to the thickness of a wire (and they are quite thin in the 80-wire cables), it might be more of an issue, but I don't think this is the case with most cables. At the end of the day, if the cable isn't too long, I don't think the signals will have attenuated sufficiently for cross-talk and noise to be an issue that can't be "seen through" by the hardware.
Actually, folding the cables probably also contributes to some cross-talk between the signals, as well as some cancelation of the signals within a given signal wire. (I mean folding with the folds parallel to the ends of the cables.)
I use 18" ATA-133 rounded cables and have not had a single problem, personally. I certainly wouldn't go much longer, though, and with most modern-day cases, there would rarely be a need for 18", let alone more.