802.11ac: 533Mbps Over WiFi

Haswell isn’t all that’s new with the 2013 MacBook Air, Apple also integrated support for 802.11ac. I wrote a primer on 802.11ac last year, but I’ll provide a quick recap here. 802.11ac is a 5GHz-only WiFi standard, with support for wider channels (80/160MHz vs. 40MHz in 802.11n) and better spatial efficiency within those channels (256QAM vs. 64QAM in 802.11n). Today, that means a doubling of channel bandwidth and a 4x increase in data encoded on a carrier, which are responsible for the significant increase in bandwidth. Usable bandwidth should also see improvements on 802.11ac as high-end access points are all expected to ship with beam forming enabled.

The first 802.11ac implementations we saw were on the smartphone side with HTC’s One and Samsung’s Galaxy S 4. Both of these devices were single antenna/single spatial stream implementations with 80MHz channels and 256QAM, resulting in a max PHY rate of 433Mbps. In his review of the HTC One, Brian documented peak performance using iPerf and a TCP transfer. In a smartphone, such high bandwidth from WiFi is really useful for improving battery life (race to sleep). In a notebook, you get the same potential improvement in battery life but there’s one more: a wireless alternative to Gigabit Ethernet.

In a 3-stream configuration given what’s available today, we’re talking about a 1.33Gbps PHY rate. Assuming better link efficiency on a notebook compared to what we’ve seen in smartphones thus far, we could be talking about a real alternative to Gigabit Ethernet - at least close to an AP. While wired GbE is always going to give you a more consistent experience, the vast majority of homes aren’t pre-wired with Gigabit Ethernet. In living situations where you can’t just run a bunch of Cat6 everywhere, but still want high speed networking, 802.11ac could be a real alternative.

The 2013 MacBook Air adds support for 802.11ac via Broadcom’s BCM4360. The controller is capable of supporting up to 3 spatial streams, but in its implementation in the MacBook Air we see a maximum of 2 used. I fully expect the 2013 rMBPs to use a third antenna to leverage all 3 streams. BCM4360 supports 80MHz channels, 256QAM and short guard intervals. The result is a max PHY rate of 867Mbps.

ASUS sent me its RT-AC66U based on the same BCM4360 silicon (coincidentally the same controller that’s in the new Airport Extreme), which I promptly used for testing the new MacBook Air. The ASUS router and MacBook Air combination worked perfectly. In the same room as the AP, I had no issues seeing the maximum 867Mbps PHY rate (above).

Within about 5 - 8 feet of the AP, I saw an average of 533Mbps using iPerf. That’s real data sent over TCP:

WiFi Performance

A 3-stream solution could definitely rival wired GbE, at least for short distances.

I then went about characterizing 802.11ac performance vs. distance to get an idea for how performance fell off as I moved away from the AP. My desk and test area is in the corner of my office, which is where I put the ASUS 802.11ac router. Performance around my desk was always up around 533Mbps.

Move around 18 feet away but remain in the same room and measured performance dropped to 450Mbps. One set of walls and another 10 - 15 feet dropped performance to between 250Mbps - 340Mbps. Another set of walls without moving much further and I was looking at 200Mbps. When I went one more set of rooms away, or dropped down to a lower level, I saw pretty consistent falloff in performance - dropping down to 145Mbps. Note that my setup is pretty much the worst case scenario for longer distances. The AP isn’t centrally located at all. If I were setting up an 802.11ac network for max coverage, I’d probably see 300 - 400Mbps in most immediately adjacent rooms.

So 802.11ac on the new MacBook Air is pretty awesome, there's just one issue...

PCIe SSD Performance Real World 802.11ac Performance Under OS X
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  • Skolde - Monday, June 24, 2013 - link

    I find the current display resolutions on these "premium" products to be very lacking for me to actually seriously consider a purchase. At least stick something in there like 1600x900.

    ....1366 x 768? Come on!

    Also - bumping the memory up to 8GB would be nice. I know it isn't build to be a workhorse, but still.

    The XPS13 from Dell seems to be a much nicer option currently.
    Reply
  • rangerdavid - Monday, June 24, 2013 - link

    1440 x 900 on this 13". Reply
  • ddriver - Monday, June 24, 2013 - link

    Why not, they put higher resolution on 5 inch phones... Reply
  • darwinosx - Monday, June 24, 2013 - link

    They put higher resolution screens on their retina laptops. The Air focus on battery life and performance above all. Reply
  • designerfx - Monday, June 24, 2013 - link

    except that's a problem. You can't take advantage of certain basic parts of *performance* if you have a terrible display. Reply
  • dsumanik - Tuesday, June 25, 2013 - link

    Here is the non TLDR version of this review:

    "intel came out with a new CPU, samsung made a new SSD and apple slapped it together last minute in an existing design. Ultimately, You get a slower, longer lasting air for a 100 bucks less that carries over all the little annoyances from last year."

    whoop dee f*ckin do……..This is apple innovation?

    "the m.2 spec wasnt far enough along to be used in this generation"

    Oh please, What a load of horse ****. I think anand, like many other review sites invested heavily in apple stock and are now trying to stop the bleeding. Apple has been deliberately stifling user upgrades for years….That is why they have proprietary connectors…ON EVERYTHING...your readers, and your reviewer knows this.

    "The only thing that hasn't changed, that perhaps should have is the display. "

    ya think? My phone has better rez. You've been criticizing PC makers for 2 years about the 1366x768 resolution, and here we have apple in 2013 and you say they "perhaps should have changed"

    ROFL

    Here are some "cheap" things they could have done to actually make this product an upgrade:

    -move the thunderbolt port beside the power connector (no more stethoscope when plugged in driving a display)
    -second thunderbolt port (now you can have 2 displays native and not be down a precious USB3)
    -16gb ram availability (now I can run several VM's comfortably when developing)
    -performance on par with last years MBA?
    -nfc support
    -4G support

    here is some mild innovation they could have done:

    -detachable screen (tablet notebook hybrid)
    -retina display
    -wireless desktop charger

    3rd tier PC makers are coming out with better hardware than apple now, this year was critical and they've dropped the ball…with the exception of the Mac pro.

    a smartwatch *could* be cool if it comes out totally water proof for active users…jogging swimming etc, if not i don't see the incentive to purchase unless it is super low cost.

    what they need to "fix" the situation

    -low cost iPhone (incoming 2013)
    -large screen iPhone (2014)
    -retina display across the board on all products (2015)
    -updated thunderbolt display, USB3 and 4k Rez for under 2000 bucks.
    -apple branded TV and home theatre system
    -thunderbolt or USB3 sync speeds on all iDevices

    Dump your apple stock now, it will bounce back but never to the highs it was previously.
    Reply
  • Glindon - Wednesday, June 26, 2013 - link

    Bored much? Reply
  • abazigal - Wednesday, June 26, 2013 - link

    Can you name me all the other manufacturers who are implementing these features, much less doing them properly?

    You want retina, there's the 13" retina MBP. And I think he was criticising manufacturers for using 1366x768 res on a 13" laptop screen. Apple uses that for their 11" MBA line, which I find is still acceptable.

    Apple decided that a slight decrease in performance was an acceptable tradeoff for longer battery life. And I am inclined to agree with them. The new processor speed still more than suffices for what typical consumers use it for anyways.

    What am I supposed to do with NFC on a laptop? You want the power source to be beside the thunderbolt port. I don't think there is quite sufficient space for 2 USB ports on one side, and so long as it hooks up to your thunderbolt display just fine, does it really irritate you so that the two cables split up?

    Personally, I feel there is nothing Apple "needs" to do. I am perfectly fine with their products. I like them, I buy them.
    Reply
  • ysaykin - Saturday, July 13, 2013 - link

    I think that in a way the comments are right. 11 inch laptops for $1000 should have some luxury features. One of those is amazing battery life, good keyboard, nice display, and good performance. The macbook air has some bases covered, but lacks the display. The resolution is fine for a sub $600 notebook but not at $1000, also a TN panel on a $1000 notebook sounds like a rip off. It should have been at least an ips panel. The longer battery life is only achievable because Mac OSx has been optimized for battery life, but if you use windows on the machine your battery takes a huge dip. So is it a good laptop, definitely, but is it worth the $1000 price? I think it's def a mac tax. Look at the Lenovo yoga which if updated to haswell would have awesome battery life, touchscreen, ips 1600x900 resolution, and convertible to tablet mode. Reply
  • rudolphbyers - Thursday, October 09, 2014 - link

    There's nothing that could replace my MacBook Air! /Rudolph from http://www.consumertop.com/best-laptop-guide/ Reply

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