Time Capsule vs. Airport Extreme + External drive speed?

[scootermaster]

I'm looking to buy a Time Capsule or the Airport extreme + external drive for Time Machine backups.

I was wondering if anyone knows if there's a significant speed difference. I know someone (Anandtech actually, I think) looked at it for a previous version, but that wasn't necessarily for Time Machine, since it wasn't "officially" supported on AEs until the most recent AC version.

I'm just wondering if there's a significant difference there, backing up over 802.11ac AND 802.11n.

I like the idea of a modular system (AE+HD) since if one part breaks, you can replace it, and it gives you modular upgradability, etc. But if the USB 2.0 is a bottleneck (and again, I'd like hard evidence not just "USB 2.0 IS SLOW!") then perhaps I'll just go with a TC.

Anyone have any experience with this setup?

 

[dave_the_nerd]

Yes.

External drives are much slower. Otherwise it works fine.

 

[scootermaster]

Yes.

External drives are much slower. Otherwise it works fine.

Is this from your own experience? Have you seen experiments? Data?

 

[JAG87]

There might be over 802.11ac, but not over 802.11n. The math is simple: 802.11n connects at max 450mbps, and USB2 is 480mbps, and in both cases real world speeds are about half of that for both technologies. So both top out at around 30 MB/s.

I currently have the 5th gen AE and backing up over time machine to a USB3 drive (at 2.0 speeds). Bollocks that it's not supported, it works just fine and is plenty fast because TM only makes delta changes. The first backup obviously takes some time.

 

[scootermaster]

It's odd nobody has tested this. Or maybe it isn't. But it sure would be nice to see actual data on this.

Granted, I didn't look too hard, but from a cursory google, I couldn't even see what sort of interface the internal HD of the Time Capsule is on. Presumably some sort of SATA, but we don't really know what sort of bus, etc., is involved (right?) so making "IT'LL BE SLOWER!" claims aren't necessarily validated by the facts.

Is there somewhere on AT we can pitch this?

 

[dave_the_nerd]

Is this from your own experience? Have you seen experiments? Data?

http://www.anandtech.com/show/4577/...nd-time-capsule-4th-gen-review-faster-wifi-/7

 

[dave_the_nerd]

There might be over 802.11ac, but not over 802.11n. The math is simple: 802.11n connects at max 450mbps, and USB2 is 480mbps, and in both cases real world speeds are about half of that for both technologies. So both top out at around 30 MB/s.

Math is never that simple. Even 802.11ac will bottleneck things because wifi is inherently crappy.

 

[JAG87]

Math is never that simple. Even 802.11ac will bottleneck things because wifi is inherently crappy.

Yup, hence why I said might. USB2 is generally fast enough when wifi is in between.

 

[scootermaster]

http://www.anandtech.com/show/4577/...nd-time-capsule-4th-gen-review-faster-wifi-/7

Ah. Those are the older versions.

 

[dave_the_nerd]

Ah. Those are the older versions.

NAS benchmarks here clock it at the same speed as the old version. (Testing the internal drive, presumably.)

http://www.cnet.com/products/apple-airport-time-capsule-802-11ac/2/

The Time Capsule uses a Broadcom BCM53019, which is a very middling, run of the mill SoC - similar chips are used by a multitude of consumer routers, and all of them have mediocre performance when working as a NAS with a USB-attached HDD.

It's CPU-bottlenecked.

 

[kbp]

Try an external on Thunderbolt. I speed tested over USB3 and Thunderbolt on a SSD. Thunderbolt was much faster (by 3x.)