The 2013 MacBook Air Review (13-inch)
by Anand Lal Shimpi on June 24, 2013 12:01 AM EST802.11ac: 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:
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...
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arkhamasylum87 - Monday, June 24, 2013 - link
Broadwell will have a refreshed GPU architecture and with the process shrinks, the gains would be more amenable to all. Although the intent to raise the GPU perf a decent percentage with dedicating more than the half the die is a big time change at Intel.rmr - Monday, June 24, 2013 - link
Hi Anand,Good review! I'm waiting for the updated review (using the i7 processor). BTW will it be possible for you to test the Air with an older 802.11g router (since some people have been complaining in the Apple forums about the Air dropping Wifi connections)? I was planning to get a new MBA but I'll be mostly using it at locations with older .11g routers.
Thanks.
Regards,
rmr
scyap - Monday, June 24, 2013 - link
Did the writer mention what OSX version was used for testing? Or I missed out?If this review was using Mountain Lion, should I expect even better battery life in Mavericks?
xype - Tuesday, June 25, 2013 - link
Yes, you should. Every dev I know who runs on Mavericks reports 10-20% better battery life (that's mighty subjective and unscientific, but I am sure AnandTech will do a proper test).Personally I'll make use of my dev account and upgrade as soon as all the dev tools I need are confirmed a running (homebrew-installed stuff mostly).
Ricopolo - Tuesday, June 25, 2013 - link
Anand, love your site. But your constant use of acronyms (like PCH, TDP, etc) that are non-household terms can be quite an obstacle to lay people, who are interested in gaining a bit of insight in tech development. Can you put together a glossary for these acronyms and put it in the footer or somewhere obvious?Thanks a lot.
SkylerSaleh - Tuesday, June 25, 2013 - link
PCH stands for Platform Controller Hub. It provides some needed utilities required to run the CPU correctly, such as display handling, connecting peripherals, DMI, etc. As a lay-mans example, the PCH supports the CPU's operation, similar to how your subconscious supports your operation. Taking over the responsibility of semi-voluntary/non-voluntary actions like breathing, so that you can think about other things.TDP stands for thermal design power. It is a measurement of the maximum amount of cooling that is needed to cool a chip in its worst case. As a rule of thumb, the higher the TDP, the more power the chip will use at peak. (However this is not a good measurement of power usage when idle.)
name99 - Tuesday, June 25, 2013 - link
Google shows up the obviously correct results for both of these very high in its list.If you want even cleaner and simpler results search on wikipedia.
I don't want to be a dick, but part of Anand being a fairly high-end site (including, for example, the variety of technical details which make it substantially more interesting than a Macworld or The Verge or WSJ review) is that it consists of an engineering aware community, which speaks in its natural language, just like any other community.
If you wish to be part of that community, the solution is not to complain that they use unfamiliar language, but to familiarize yourself with that language. It's not hard --- more so than ever before in the past you can learn what you need to just by scanning Google and wikipedia. And if you want to understand more details, again it's easier than its ever been before --- just look over the review articles either on this site, on Ars Technica (for the simplest introduction) or on David Kanter's Real World Tech (for the most sophisticated introductions you can probably get for free on the internet).
jb510 - Wednesday, June 26, 2013 - link
Well said. It's worth noting that even some of us very technical folks have to look up a lot of terms and acronyms reading here as the spectrum of content is so broad. However, I greatly prefer the clean without reference to terms style of AT to the cumbersome reading if copy that is interrupted constantly to define things. Unless you're reading the print edition of AT, the whole internet is just one click away.robco - Tuesday, June 25, 2013 - link
The updated Airs seem pretty sweet. I use my laptop as my primary machine, so I'll probably wait for the rMBP to get updated. I'm also curious to see how well the Iris 5100 graphics compare to the HD 5000. An IPS display would have been a nice upgrade, but I can see why Apple decided to make upgrades in other areas instead.The WiFi snafu is interesting. I'm not sure if Apple missed it, or figured it would be a while before most users would upgrade to ac and decided to go ahead and ship it in time for WWDC. As for battery life, even the numbers under heavy workload are impressive for such a small machine. I'm curious to see how well the battery life numbers improve for other ultrabooks as they switch to Haswell running different OSes. I would also like to see if or how well battery live improves after OS 10.9 is released this fall.
Abelard - Tuesday, June 25, 2013 - link
Thanks for the thorough review, Anand. The battery life you were getting is very impressive.I'm curious how the MBA will perform running OS X Mavericks, though. Developers and early adopters seem to be reporting battery life improvements. It's possible Mavericks could squeeze another hour or two out of the 2013 MBA.