AirportextremeNetworking code in OS X Mountain Lion is slowing down file transfers over the Apple Filing Protocol (AFP) and Microsoft's Server Message Block (SMB), according to examinations done by both Ars Technica and AnandTech.

The issue affects the new MacBook Air models that come equipped with the 802.11ac Wi-Fi technology. The new MacBook Air and Apple's new AirPort Extreme base station are the first Apple products to use the new Wi-Fi technology.

Anandtech discovered that the TCP window size for file transfers in OS X was too small to reach the potential throughput on many file transfers, slowing data transfers from a potential 533Mbps down to 170Mbps.

The bad news is that in its shipping configuration, the new MacBook Air is capable of some amazing transfer rates over 802.11ac but you won’t see them when copying files between Macs or PCs. The good news is the issue seems entirely confined to software. I’ve already passed along my findings to Apple. If I had to guess, I would expect that we’ll see a software update addressing this.

Ars Technica confirmed AnandTech's findings, and went a bit further. The site discovered that when running Windows 8 in Boot Camp, the new MacBook Air saw file transfer speeds significantly higher than under a comparable setup in OS X Mountain Lion.

Some variation between the two operating systems is to be expected. They're very different under the hood, after all, and Microsoft's strong commitment to the enterprise (and the file servers therein) makes it unsurprising that Windows' file transfer speeds are generally a bit faster than OS X's. However, the discrepancy between the Windows 802.11ac speeds and OS X speeds is too large to be explained away by networking optimizations alone. Windows is, at best, about nine percent faster over Gigabit Ethernet and 30 percent faster over 802.11n, but it's 218 percent faster over 802.11ac.

Ars' OS X wireless setup saw transfer speeds of 21.71MB/s on SMB, and 47.26MB/s on a comparable Windows 8 setup under Boot Camp.

The issues also exist under the developer beta of OS X Mavericks, but both sites expect Apple to release a software fix for OS X that will solve the file transfer issues.

Top Rated Comments

komodrone Avatar
109 months ago
some people are feeling this:
Score: 10 Votes (Like | Disagree)
parapup Avatar
109 months ago
One would still think these issues should be more uncommon on Macs than they are since ”Apple makes both the hardware and the software”, no?
Haha the delusion of integration! It took a third party for Apple to do their testing and analysis for them after the product release. The Windows part gotta hurt the fanboys real bad :)
Score: 6 Votes (Like | Disagree)
Nightarchaon Avatar
109 months ago
Haha the delusion of integration! It took a third party for Apple to do their testing and analysis for them after the product release.

Isnt that how apple do all the testing,

Apples process is something like this

step one, J.Ive design a case nothing with a reasonable performance can fit into.

Step Two, the hardware engineers go out and shoehorn whatever they can find that can kind of fit into that case.

Step Three, Apples marketing team has to spin the reason you can get a PC for a tenth the price with 4x the power almost solely on the J.Ive designed case and a load of specs that don't work yet and might be patched in later.

Step four, build a giant ring shaped building to put all the money in the middle of and swim about like Scrooge McDuck.

Now im not an apple hater, i love the OS, i just wish they would u-turn from this sealed unit lockdown, all our products are disposable, kick they are on , when its easier to replace the Harddisk in my PS3 when it fails than my iMac, something is seriously out of whack.
Score: 4 Votes (Like | Disagree)
star-affinity Avatar
109 months ago
Not a big surprise. New hardware often has driver/software problems. No need to return new MacBook Airs. They will be fixed in a software update ;)

One would still think these issues should be more uncommon on Macs than they are since ”Apple makes both the hardware and the software”, no?
Score: 4 Votes (Like | Disagree)
Plutonius Avatar
109 months ago
People must be holding it wrong :D.
Score: 3 Votes (Like | Disagree)
thejadedmonkey Avatar
109 months ago
In other words, a typical 1st revision Apple product.
Score: 3 Votes (Like | Disagree)

Related Stories

studio buds family

Beats Studio Buds Debuting Today With Active Noise Cancellation, Stemless Design, and More for $150

Monday June 14, 2021 8:00 am PDT by
We've seen a lot of teasers about the Beats Studio Buds over the past month since they first showed up in Apple's beta software updates, and today they're finally official. The Beats Studio Buds are available to order today in red, white, and black ahead of a June 24 ship date, and they're priced at $149.99. The Studio Buds are the first Beats-branded earbuds to truly compete with AirPods...
youtube apple tv

YouTube Discontinuing 3rd-Generation Apple TV App, AirPlay Still Available

Wednesday February 3, 2021 3:09 pm PST by
YouTube is planning to stop supporting its YouTube app on the third-generation Apple TV models, where YouTube has long been available as a channel option. A 9to5Mac reader received a message about the upcoming app discontinuation, which is set to take place in March.Starting early March, the YouTube app will no longer be available on Apple TV (3rd generation). You can still watch YouTube on...
iPhone 13 Dummy Thumbnail 2

Kuo: iPhone 13 to Feature LEO Satellite Communications to Make Calls and Texts Without Cellular Coverage

Sunday August 29, 2021 7:39 am PDT by
The iPhone 13 will feature low earth orbit (LEO) satellite communication connectivity to allow users to make calls and send messages in areas without 4G or 5G coverage, according to the reliable analyst Ming-Chi Kuo. In a note to investors, seen by MacRumors, Kuo explained that the iPhone 13 lineup will feature hardware that is able to connect to LEO satellites. If enabled with the relevant...
YouTube Picture in Picture Feature

YouTube Premium Subscribers Can Now Use iOS Picture-in-Picture: Here's How

Wednesday August 25, 2021 3:55 am PDT by
Google has rolled out picture-in-picture support as an "experimental" feature for YouTube premium subscribers, allowing them to watch video in a small window when the app is closed. If you're a premium YouTube subscriber looking to try out picture-in-picture, follow these steps: Launch a web browser and sign into your YouTube account at YouTube.com. Navigate to www.youtube.com/new. Scroll...
os x mountain lion macs 16x9 2

Apple Makes OS X Lion and Mountain Lion Free to Download

Wednesday June 30, 2021 12:19 pm PDT by
Apple recently dropped the $19.99 fee for OS X Lion and Mountain Lion, making the older Mac updates free to download, reports Macworld. Apple has kept OS X 10.7 Lion and OS X 10.8 Mountain Lion available for customers who have machines limited to the older software, but until recently, Apple was charging $19.99 to get download codes for the updates. As of last week, these updates no...
tim cook spring loaded event

Gurman: Apple Planning Multiple Events for the Fall, M1X MacBook Pros to be Available by November

Sunday August 15, 2021 12:07 pm PDT by
Apple is planning to hold multiple events this fall, which will collectively include the launch of new iPhones, Apple Watches, updated AirPods, revamped iPad mini, and the redesigned MacBook Pros, according to respected Bloomberg journalist Mark Gurman. In his latest weekly Power On newsletter, Gurman says that much like last year, Apple will hold multiple events this coming fall, with the...
apple screen time screen icons

Persistent Kids Finding Loopholes in Apple's Screen Time Limits

Tuesday October 15, 2019 9:44 am PDT by
Apple is currently engaged in a cat-and-mouse game with persistent kids looking to circumvent Screen Time restrictions, but the company has been receiving some criticism for not moving quickly enough to lock down some of the loopholes, reports The Washington Post. A few of the loopholes and ways for parents to shut them down are documented on the site Protect Young Eyes, while these and...
anker lightning cable mfi

Unwrap a New Apple Device? Stock Up on Extra Certified Lightning Cables for as Little as $6

Monday December 25, 2017 5:45 am PST by
If you unwrapped an Apple product today it likely came with one of the company's first-party Lightning cables, but having an extra on hand is always a good idea, so you can place it in other rooms in your house, in your car, or in a bag when you travel. For that reason, now's a good time to shop for third-party Lightning cables that are cheaper than Apple's own accessory, but still Made For...
personal hotspot 1

Apple Acknowledges Personal Hotspot Issues Affecting Some iOS 13 and iPadOS 13 Users

Saturday March 21, 2020 10:04 am PDT by
In an internal document distributed to Apple Authorized Service Providers this week, obtained by MacRumors, Apple has acknowledged that some iOS 13 or iPadOS 13 users may experience issues with Personal Hotspot. Apple has told Authorized Service Providers to expect customers who are unable to connect to a Personal Hotspot or experience frequent disconnection from one. Customers may also...
macos monterey safari beta 3

macOS Monterey Beta 3: Apple Redesigns Safari Tab Interface Following Complaints

Wednesday July 14, 2021 11:39 am PDT by
In the third developer beta of macOS Monterey, which came out this morning, Apple has overhauled the design of Safari, making the tab bar more similar to the current tab bar in macOS Big Sur. The prior Safari design did away with the dedicated URL and search interface, instead allowing any individual tab to be used for navigation input. Tabs were also all arranged at the top of the display...