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
141 months ago
some people are feeling this:
Score: 10 Votes (Like | Disagree)
parapup Avatar
141 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
141 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
141 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
141 months ago
People must be holding it wrong :D.
Score: 3 Votes (Like | Disagree)
thejadedmonkey Avatar
141 months ago
In other words, a typical 1st revision Apple product.
Score: 3 Votes (Like | Disagree)

Popular Stories

Delta Feature

Delta Game Emulator Now Available From App Store on iPhone

Wednesday April 17, 2024 9:58 am PDT by
Game emulator apps have come and gone since Apple announced App Store support for them on April 5, but now popular game emulator Delta from developer Riley Testut is available for download. Testut is known as the developer behind GBA4iOS, an open-source emulator that was available for a brief time more than a decade ago. GBA4iOS led to Delta, an emulator that has been available outside of...
iOS NES Emulator Bimmy Feature

NES Emulator for iPhone and iPad Now Available on App Store [Removed]

Tuesday April 16, 2024 11:33 am PDT by
The first approved Nintendo Entertainment System (NES) emulator for the iPhone and iPad was made available on the App Store today following Apple's rule change. The emulator is called Bimmy, and it was developed by Tom Salvo. On the App Store, Bimmy is described as a tool for testing and playing public domain/"homebrew" games created for the NES, but the app allows you to load ROMs for any...
iPhone 15 Pro Action Button Translate

All iPhone 16 Models to Feature Action Button, But Usefulness Debated

Tuesday April 16, 2024 6:54 am PDT by
Last September, Apple's iPhone 15 Pro models debuted with a new customizable Action button, offering faster access to a handful of functions, as well as the ability to assign Shortcuts. Apple is poised to include the feature on all upcoming iPhone 16 models, so we asked iPhone 15 Pro users what their experience has been with the additional button so far. The Action button replaces the switch ...
maxresdefault

Hands-On With the New App Store Delta Game Emulator

Wednesday April 17, 2024 12:19 pm PDT by
A decade ago, developer Riley Testut released the GBA4iOS emulator for iOS, and since it was against the rules at the time, Apple put a stop to downloads. Emulators have been a violation of the App Store rules for years, but that changed on April 5 when Apple suddenly reversed course and said that it was allowing retro game emulators on the App Store. Subscribe to the MacRumors YouTube channel ...
iOS 18 Siri Integrated Feature

iOS 18 Will Add These New Features to Your iPhone

Friday April 12, 2024 11:11 am PDT by
iOS 18 is expected to be the "biggest" update in the iPhone's history. Below, we recap rumored features and changes for the iPhone. iOS 18 is rumored to include new generative AI features for Siri and many apps, and Apple plans to add RCS support to the Messages app for an improved texting experience between iPhones and Android devices. The update is also expected to introduce a more...