The Joys of 802.11ac WiFi
by Jarred Walton on July 8, 2013 8:15 PM ESTClosing Thoughts (for Now)
It’s really up to the notebook manufacturers to make sure that their WiFi implementations are up to snuff, and that means doing more than a quick test for connectivity in ideal test conditions. The QA and engineering departments at the very least ought to be testing at 5, 25, 50, and 100 feet, using standard Windows operations (i.e. not just IxChariot or iPerf). If there are issues, they should be ironed out before customers (and reviewers) get the product. With that said, a good foundation for wireless networking can go a long way toward improving bandwidth and stability of your connection.
Intel’s adapters aren’t always the best, but they’re rarely the worst, provided you get one of the non-budget offerings (i.e. avoid the 1000 and 2000 series parts). Realtek unfortunately comes in near the bottom of my ranking list in many cases, but most notebooks with Realtek WiFi are already cutting corners—they’re the 1x1:1 2.4GHz only solutions that are so common. The fact is, whether you're using an adapter from Qualcomm/Atheros, Broadcom, Marvell, Realtek, or Ralink, you can have a good adapter in some cases or a downright awful one in others. Broadly speaking, most solutions with two streams end up being better than any of the single stream solutions.
Of course, it's not just about spatial streams. Oddly enough, for a company that has been on the forefront of wireless technologies, as Anand detailed in our MacBook Air 2013 review OS X is not scaling TCP window size beyond 64KB and thus fails to get optimal performance out of 802.11ac. (I assume an OS/driver patch will address this at some point, but that hasn't happened yet AFAIK.) OS and driver issues can definitely put a clamp on WiFi performance, which again is why the notebook makers need to exercise due diligence and test in real-world scenarios to ensure their hardware is working properly.
As I said earlier, one of the best things about 802.11ac wireless is that it raises the bar for wireless adapters. No one can get away with selling you an 11ac adapter without including at the bare minimum a dual-band chipset with support for 5GHz and 2.4GHz networks. If you live in a packed subdivision or apartment complex, 5GHz networking is almost required these days. Ideally, though, I want more than just the bare minimum; I want two 80MHz streams on my 802.11ac connections, and three would be even better. Intel’s 7260 provides two streams, and so do most of the current crop of 802.11ac routers. Hopefully, we won’t see as many solutions going for the bottom of the barrel single stream implementations; they’re not worse than 802.11n, but they’re not much better than two stream 5GHz 802.11n either.
Consider this a warning shot across the bow of the notebook manufacturers: we’re going to be paying more attention to your wireless implementations going forward. I can understand why a $500 or less budget laptop needs to cut every corner possible to hit that price point, but when we’re looking at $1000+ laptops we don’t want to see such blemishes. It may not always be as painful as using a bad LCD on an otherwise excellent laptop, but a bad WiFi implementation that loses connectivity if you’re more than 40 feet from the router in can be even worse in some cases.
We’ll be doing some full reviews of 802.11ac routers in the near future, including the Western Digital AC1300 and Linksys AC1200. The full reviews will better characterize performance as well as other features. Until then, at least right now it looks like most 802.11ac routers are using two streams (867Mbps maximum theoretical throughput), which is at least a nice upgrade over the 300Mbps so many 802.11n routers offer. Meanwhile, Apple's latest AirPort Extreme and Time Capsule go whole hog and give us three streams and up to 1300Mbps. Now if I could just get (Windows) laptops with three 802.11ac streams, I might actually be willing to give up my Gigabit Ethernet and wires!
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thetoad30 - Thursday, July 11, 2013 - link
I think you are sorely mistaken with this article. Here's why:802.11ac will combine up to three 80 mhz 5 GHz streams. As each channel is 20MHz, you're looking at four channels per stream, by three streams, meaning 12 channels being used by ONE router. Since there are only 21 channels right now, one router takes up more than half the available spectrum in the 5GHz channel.
Remember 11n in the 2.4 GHz spectrum? Why didn't anyone get 40MHz channels? Because there were only three non-overlapping channels in the spectrum, and the number of people using it meant that interference was all but impossible to avoid in common neighborhoods. 11ac just brings that problem to the 5 GHz channel.
Second, Apple doesn't allow 40MHz three stream mode in their 2.4 GHz band - you are limited to 2x2 at 270 mbps for the same reason I outlined above.
People think that the 5GHz spectrum is the answer for interference - and it was because it had so many options to choose from to limit interference - but now that you're combining channels and soaking up more bandwidth, it will soon be just like the 2.4 GHz fiasco.
Just thought you'd want readers to know this before pouring money into products that eventually will have the same problems as before.
JarredWalton - Thursday, July 11, 2013 - link
You're right that the amount of spectrum/channels being used by one router is higher with 11ac, but what you're not mentioning is range. The biggest issue with 2.4GHz (and the reason no one is doing 900MHz WiFi these days) is that the range on 2.4GHz is much greater. With a moderate yard (0.14 acres or so), I don't see my 5GHz signal much beyond my property, if at all. Most people who want bandwidth are really only looking at bandwidth within their home, in which case 11ac can be an excellent solution. On 2.4GHz, I can at least "see" anywhere from eight to twelve networks from my house, and that makes it extremely difficult to get a 40MHz channel. 3x3:3 can still get better throughput than 2x2:2, thanks to the extra stream, but for shorter distances 5GHz 11n is often two or three times faster than 2.4GHz 11n, and 5GHz 11ac can be another doubling in performance over 5GHz 11n.I'm not saying 11ac is for everyone, but if you want higher bandwidth within a more limited area, it can be awesome. 40MBps to my downstairs HTPC is nearly four times what I got with the Amped Wireless router/repeater combination, also functioning on 5GHz. (And on 2.4GHz, the Amped Wireless only managed 4-6MBps most of the time.)
thetoad30 - Thursday, July 11, 2013 - link
Huh. I had a whole comment block that explained the issues with 11ac and some errors in the article and it appears to have been deleted. I wasn't disrespectful or arrogant either. Wondering if censoring is happening or if my account is messed up?thetoad30 - Thursday, July 11, 2013 - link
Never mind - apparently it's working now.Micropterus - Thursday, July 11, 2013 - link
Did this Mythlogic Pollux 1613 happen to have the Samsung PM841 mSATA SSD? Preferably 512GB, that you could test, please? :)trip1ex - Friday, July 12, 2013 - link
I just wired my house with Cat6. It isn't just about pure speed but latency for me. The WMC experience likes low latency.Conficio - Friday, July 12, 2013 - link
What about bufferbloat testing? For many throughput is only half of the story, latency in Wifi solutions is a big, big issue as well. Could you please consider testing the bufferbloat behavior of these implementations? Also add the buffer characteristics, size in hardware/drive if possible.http://www.bufferbloat.net/
theduckofdeath - Sunday, July 14, 2013 - link
You seem to like Apple a lot. I mean, they're a nice company and all, but, I really think the majority would enjoy seeing references to stuff adopted by a wider demographics once in a while?JarredWalton - Monday, July 15, 2013 - link
The only Apple product in my house is an iPod Touch 4th Gen, and I didn't even buy that. However, I've handled enough Apple MacBook Pro laptops and iPads and iPhones to know that they make a good product. I personally don't like OS X, and I hate the elitist mentality that seems to pervade the Apple user base, but credit where credit is due: Apple has pushed the state of the art in many areas. Having a rabid cult following helps, sure, but if the iPhone, iPod, iPad, etc. had lousy hardware and software, none of the devices would have seen the success they've enjoyed. You pay through the nose on some of their products, but generally speaking at least you get a quality result...provided you prefer running OS X, of course.misaki - Tuesday, July 16, 2013 - link
For years I've had problems with wifi dropping out/crashing when doing lots of file transfers and requiring reboots of the laptop/router using many different chipsets. But every time I tried to google it, I could never find any meaningful conversation on it. It's nice to know I wasn't the only one with these problems.