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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lordbannon - Monday, July 8, 2013 - link
I've had two wireless ac routers working as a bridge between the two main network nodes in my house for a few months, and while the latency clearly isn't quite there yet, for file transfers I'm not really seeing any issues. Its the first time I've actually not been concerned with getting around to wiring my house!DaveLessnau - Tuesday, July 9, 2013 - link
I've got Netgear R6300s in two rooms configured in Bridge Mode to my original R6300 (configured as a regular Access Point) using 5GHz. Transferring files across the LAN (i.e., from an SSD in the Windows 8 computer on one Bridge to the SSD in the Windows 7 computer on the other Bridge) doesn't seem very good to me. My speeds (according to Windows) are:- a single 2.69 GB file transferred at 14.2 MB/s (114 Mbps).
- 1,223 items totaling 2.93 GB transferred at just about the same speed (13.2 MB/s or 106 Mbps).
That's about half the real-world speed I'd expect transferring to a slow USB 2.0 drive. Considering that all of these R6300s are 802.11ac devices, I'd have expected at least two or three times that speed.
Guspaz - Tuesday, July 9, 2013 - link
I get better speeds out of my 2x2 802.11n network...Spoelie - Tuesday, July 9, 2013 - link
Do all the R6300s use the same channel? Potential for interference there. Max speed you will only see when there's only one client actively sending on the network, no competing networks on the same channel and the other client is wired to the AP.DaveLessnau - Tuesday, July 9, 2013 - link
Unfortunately, as far as I can tell, the R6300s in Bridge Mode can't specify their channel. The channel is set in the Access Point router and whatever it's set to is what all the bridges use. It looks like the only way to specify different channels for each bridge is to have one of the bridges use 2.4GHz and have the other use 5GHz. One of these days, I'll get around to testing how that works. But, still, these R6300s are supposed to be capable of 1300 Mbps. Channel conflict or not, I really expected better than 8% of the rated speed.DaveLessnau - Tuesday, July 9, 2013 - link
Oops. I forgot to mention that there aren't any other 5GHz networks in the area. Actually, there's only one other 2.4GHz network that's within range. That's a nice benefit of living in a standalone house in a neighborhood populated mostly by little ol' ladies. :)virgahyatt - Thursday, July 25, 2013 - link
If they are acting as wireless bridges then you can't set different channels. However there is no interference issue in that scenario. Though wireless bridging increases overhead and therefore slows down your actual transfer speed.0ldman79 - Thursday, July 11, 2013 - link
Netgear may be your problem. I've never had any luck with Netgear routers for myself or any of my customers.Linksys/Cisco seem OK, but the almost exclusive use of Broadcom chips limit them.
Atheros makes some really nice chipsets, but they don't have good market penetration in consumer level equipment.
I've got quite a bit of Atheros equipment in the air and I've done quite a bit of testing. Atheros beats just about every one else in range and throughput.
Mokona512 - Friday, August 16, 2013 - link
What router companies usually fail to mention is that high speed wifi are broken up into multiple streams.the problem with this is that network applications which only make 1 connection, will only use a single stream.
This means that in order to reach your full speed, you need to get 3-4 connections going.
you can easily test this yourself, on your network create an FTP server or any other basic server that you can download files from
Then use a download manager such as down them all for firefox. then have it download and compare your speeds.
with 802.11ac, speeds quickly drop with distance because it can not maintain something as high as 256QAM for more than a few feet. and generally after about 20 feet, each stream will give around 100-120mbit/s of performance.
At best, wifi only offers around 40-50% of the advertised speed It has been this way since 802.11g (802.11b offers over half, you could expect around 8-9mbit/s on an 11mbit connection)
windows file transfer will often only make 1 connection but depending on the router, different streams can take turns handling a single connection which leads to a small speed boost, but nothing close to a true multi connection.
The good thing about the r6300 is that is has very high end wifi radios and they can be heavily optimized so netgear may release more updates to further optimize the wifi, or the community behind tomato or some other open firmware, will implement some of the latest optimizations.
PS if just having a slower client connected to the 5GHz network will slow the 5GHz network down or cause the router to drop to an N450 mode, so if you have 1 router set up as a bridge and the main router set up as normal where the second router shows up as a client, then make sure no non ac1300 client is connected to the 5GHz.
If the network has to compensate for a slower client then it also disables all AC tailored optimizations.
SlyNine - Saturday, January 10, 2015 - link
I do not believe that last part to be true. Ac afaik will stay at ac speeds even with an n device.You really need to site some sources, because I'm calling bs on most of your rant.