Nowhere near N

[kilgore]

need ideas here. for those who actually read this whole thing, thanks for your time.

i recently (december?) upgraded to a wireless n airport express. two main reasons: airtunes and wireless n.

now airtunes works great, no problems there. but as for supposed wireless n speeds...

little disappointments here and there led me to perform some simple tests. idea is transferring a ~350mb file between a macbook and macbook pro via the ape.

ape was running on wireless n only mode, on the 5GHz band (supposedly the fastest configuration).

validated the link speeds via network utiliy: macbook was at 300Mbit/s, and the mbp that was a bit farther away from the ape was at 270Mbit/s -- at any rate these are most definitely NOT just G-speeds.

here are my results:

control/baseline: 351.1MB from external hdd via FW800 to the MBP: 13.14s, i.e., 213.76Mbps

same file from MBP to MB via APE w/ WPA2 security on: 4'59" (9.39Mbps)
same file from MBP to MB via APE w/ no security: 5'42.25" (8.21Mbps)

using another 351MB file:

MB to MBP with WPA2: 4'55.59" (9.50Mbps)


just to validate whether it was like OS operations getting in the way or hard drive speeds being throttled somehow, i did a direct wireless link between MB and MBP by creating a network on the MBP to which the MB connected. link speed achieved was 130Mbit/s.

351MB file from MB to MBP with no security: 1'08.01" (41.29Mbit/s)

and for good measure, i tried out the APE in g-mode by configuring it to accommodate g-devices and did a transfer from the MB to a windows laptop with a G wireless card.

MB (connected at 130Mbit/s) to windows laptop (connected at 18Mbit/s), no security: 7'21.91" (6.35Mbps)


okay, so there. i think the numbers speak for themselves, even if both the MBP and MB were connected via wireless N, the file transfer speeds left much to be desired.

anyone care to take a stab at a reason, and more importantly a solution? hopefully i'm missing something basic here...

other notes:
- OS and all hardware updated
- while the test was being done only two devices were connected to the ape (source and target devices), and neither was doing anything else (e.g., no downloads or anything network/disk/cpu intensive)

[kilgore]

googled a bit and found that at least some people really do get good speeds with airport and wireless n.

http://www.barefeats.com/net80211n.html

i compute their wireless n transfer speed at around 30Mbps -- which is acceptably within the claim that it's 5 times faster than G (my own G transfer speed was 6.35Mbps).

[ijingo]

Good you figure this out, planning to upgrade on N.

[kilgore]

I'm still not getting expected speeds, but if I do find out anything I'll post back here. If/when you do upgrade please let me know too how it goes on your end.

[bacchus_3]

you'd have to account for radio interference. Comparison between g and n mode did show you that n-mode is obviously faster with your current configuration. When it comes to wireless technologies you can't get close or over 70% of the published performance on average conditions. I actually have better performance from your N-mode only APE on my AEBS. It can go up to 14MBps when it was used for file transfer and Time Machine - but normal occasions it goes down to 6MBps. G-mode yields average of 4MBps. I get better performance for N which is already a good deal considering I bought the AEBS n for that.

[kilgore]

good point about radio interference. true that although network utility might report a link speed of 300 or 270 Mbps, actual transfers are subject to interference (not to mention OS and other internal operations) that effectively reduce maximum possible transfer rate.

i DID however try a direct wifi transfer between the two macs which yielded great results (41 Mbps). granted, the macs were only a few feet apart. if i get OC again about this i'll do a trial with the two macs and the APE right next to each other to minimize the effects of radio interference.

oh, also, running at 5GHz should be better than 2.4GHz as far as interference goes (most current cordless phones run at 2.4GHz -- which is why i got a 900MHz one). but again, lots of other stuff causes interference.

i guess i just want to duplicate or at least approximate the results of the barefeats article i quoted above. not necessarily in absolute bps terms, but at least in relative speeds between G and N modes. they achieved 3.8x. my personal best is 1.48x. malayo.