Tuesday, February 13, 2007

Airport Extreme vs Airport Express

Dave asked how the new Airport Extreme fairs against 802.11g routers, and I was curious myself, so I ran some tests comparing the Extreme to the Express.

My router is in my living room. I have a Mac Pro (802.11n enabled) about 20 ft. away in the same room. From an upstairs bedroom about 50 ft. away from the router, I copied a 10 MB file from my MacBook Pro to my Mac Pro over the wirless network. I ran the test three times for each configuration: Airport Express, Airport Extreme before running the 802.11n enabler on my laptop, and Airport Extreme after running the enabler.

I created a 10 MB file of random bits like so:

dd if=/dev/urandom of=10MB bs=1024 count=10000

And I used SSH to copy the file over the network:

dd if=10MB | ssh macpro dd of=/dev/null

I'm sure this wasn't the most optimal way to copy a file over the network, but I think it provides a fair comparison. I knew my network was slow, but I was still a little surprised by the results. I hope my copying method is at fault (yes, those are megabits):

  • Express: 1.8 Mb/s
  • Extreme (before enabler): 3.6 Mb/s
  • Extreme (after enabler): 8.4 Mb/s

As both computers are on the wireless network, you have to consider that the actual data rate is at least doubled, i.e. the data has to go over the air from the laptop to the router and then back over the air again to the desktop. I could have connected one computer directly to the router using a cable, but the Express doesn't support this, and 100% wireless is more representative of my use.

Despite the slow performance, the Extreme performed twice as fast as the Express even before I enabled 802.11n. After I enabled 802.11n, the Extreme ran almost 5X as fast (4.6X to be a little more precise). On the bright side, transferring video around my network just got a lot less painful.


Blogger Pat Niemeyer said...

When I copy the 10MB file with scp from my desktop (wired) to my laptop with a Linksys G I get a transfer rate of about 14Mbit/s (about 1.7MB/s)

I guess worst case cut that in half for two clients... and maybe using ssh in that way adds some overhead...

But that still sounds slow. I thought N was supposed to give you much higher rates... hundreds of megabits.

7:04 PM  
Blogger Bob said...

I would guess two computers talking on the same wireless network at once would more than halve the bandwidth, i.e. half is the best not worst case.

As for the slow performance, my conditions were far from ideal, i.e. one computer far away in a different room.

Still, the N router far outperformed the G router. I would guess you'd see about 70Mbit/s from an N router.

I also live in a condo and have a few other wireless networks within range.

7:16 PM  

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