Airport Time Capsule: Speedy Backups, Efficient Transfers

The Apple AirPort Time Capsule is a NAS server that offers fast Wi-Fi and easy backup for Mac users. When connected to a computer via wired Gigabit connection, the Time Capsule offers 26MBps and 29MBps, respectively, for writing and reading. These are fast speeds, about the same as that of a USB 2.0 external hard drive. The Time Capsule is also twice as fast at writing and over three times as fast at reading when compared to the Airport Extreme.

The Time Capsule is twice as fast at writing and three times as fast at reading compared to the Airport Extreme

The Time Capsule is also able to operate a 2.4GHz network to support older 802.11b-, -g, and -n clients, as well as a 5GHz network to support 802.11a and 802.11n clients. This makes it a versatile option for those with older devices.

While the Time Capsule is fast, there is a known issue with OS X that hinders the router's file-transfer performance. This issue has not been confirmed by Apple, but the company is reportedly working on a solution.

The Time Capsule is slower than single-volume dedicated home NAS servers

The current theory, first published at Anandtech, is that OS X is not properly scaling TCP window size during file transfers to allow the MacBook Air’s 802.11ac client adapter to achieve peak performance. While Apple has not confirmed this to be the problem, the company is aware of the performance discrepancy and is reportedly working on a solution.

The Time Capsule is twice as fast at writing and over three times as fast at reading when compared to the Airport Extreme. Its SATA II interface makes it a considerably faster experience compared to the cheaper USB 2.0 dock solution.

Despite being slower than single-volume dedicated home NAS servers, the Time Capsule's speed is fast enough for most data-sharing and Time Machine backup needs.

The Time Capsule is faster than the previous generation of Time Capsule

Compared with single-volume dedicated home NAS servers, the Time Capsule was still significantly slower. Nonetheless, its speed is fast enough for most data-sharing and Time Machine backup needs. If you use an 802.11ac-enabled Mac, note that Time Machine backup would then be about three times faster than with the previous Time Capsule.

The Time Capsule's SATA II interface makes it a considerably faster experience compared to the cheaper USB 2.0 dock solution. It ends up being twice as fast at writing and over three times as fast at reading to use the Time Capsule over the Airport Extreme.

Based on my experience testing 802.11ac routers with Windows machines, I expected the 802.11ac Time Capsule to be considerably faster than the 802.11n model. And that’s certainly what my WiFiPerf results indicate. But these real-world file transfers defy that expectation. The current theory, first published at Anandtech, is that OS X is not properly scaling TCP window size during file transfers to allow the MacBook Air’s 802.11ac client adapter to achieve peak performance. While Apple has not confirmed this to be the problem, the company is aware of the performance discrepancy and is reportedly working on a solution.

The Time Capsule is faster than the 802.11n model

Compared with single-volume dedicated home NAS servers, the Time Capsule is slower. Nonetheless, its speed is fast enough for most data-sharing and Time Machine backup needs. If you use an 802.11ac-enabled Mac, note that Time Machine backup would then be about three times faster than with the previous Time Capsule.

The Time Capsule's SATA II interface makes it a considerably faster experience compared to the cheaper USB 2.0 dock solution. It ends up being twice as fast at writing and over three times as fast at reading to use the Time Capsule over the Airport Extreme.

The current theory is that OS X is not properly scaling TCP window size during file transfers to allow the MacBook Air’s 802.11ac client adapter to achieve peak performance. While Apple has not confirmed this to be the problem, the company is aware of the performance discrepancy and is reportedly working on a solution.

The Time Capsule's SATA II interface makes it faster than the USB 2.0 dock solution

The Time Capsule is a fast piece of kit, offering 26MBps and 29MBps, respectively, for writing and reading when connected to a computer via wired Gigabit connection. These speeds are about the same as that of a USB 2.0 external hard drive. However, the Time Capsule's SATA II interface makes it faster than the USB 2.0 dock solution.

The Time Capsule is twice as fast at writing and over three times as fast at reading when compared to the Airport Extreme. When compared to single-volume dedicated home NAS servers, the Time Capsule is slower, but its speed is still fast enough for most data-sharing and Time Machine backup needs.

The Time Capsule can also operate a 2.4GHz network to support older 802.11b-, -g, and -n clients, as well as a 5GHz network to support 802.11a and 802.11n clients. If you use an 802.11ac-enabled Mac, note that Time Machine backup would then be about three times faster than with the previous Time Capsule.

The current theory, first published at Anandtech, is that OS X is not properly scaling TCP window size during file transfers to allow the MacBook Air’s 802.11ac client adapter to achieve peak performance. While Apple has not confirmed this to be the problem, the company is aware of the performance discrepancy and is reportedly working on a solution.

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