Slow Wireless LAN in Leopard

All right, I've spent the past 12 hours (on and off, of course) looking through all the threads in here, doing a lot of experimentation, and a bunch of clean installs and whatnots, and I've decided to start a new thread, since in many of the said threads, some people seemed to have similar issues, but the other issues in the same threads seem to be different problems, and it just becomes confusing when you try to trouble shoot something and people are talking about different problems.


So, this thread is specifically for people who satisfy these criteria under Leopard:

1) You're having issues with very slow file transfers in your *local network* when at least one end is connected wirelessly; that is to say, when both ends are connected to the router via ethernet, you see no problem at all.

2) Your wireless connection doesn't display problems when connecting to the internet.

3) It is not specifically an 802.11n issue; i.e., the problem can be duplicated when in Mixed b/g only mode and/or using an 802.11g router.

4) It's not a router connection issue; i.e., your wireless connection isn't being dropped, and you are able to find your AP and connect to it without any problems.




So basically, that more or less sums up my problem. My equipments:

MacBook Core2Duo 2.2GHz, 802.11b/g/n, OSX 10.5.2
iMac Core2Duo 2.13GHz, 802.11b/g/n, OSX 10.5.2
Router 1: TRENDnet TEW-631BRP (Draft N router), H/W V3.0R, FW v.1.0.3.7
Router 2: NETGEAR WGR614 v.5 (g), FW v.1.0.3_1.0.3

Internet: RCN Cable, 20Mbps/2Mbps


In my usual setup, the iMac is connected via Ethernet and the Macbook is connected wirelessly.


I know that this is a Leopard problem, but I'm not so sure it's a 10.5.2 specific problem. Let me explain.

I'd been using the TRENDnet more or less happily for the last couple of months. My iMac and Macbook have been in sync in terms of Leopard versions, so I know things were OK till last night when I first noticed problems. Transferring a large video file from the iMac to the Macbook would start off fine, then really slow down, and finally almost completely halt. Naturally, I blamed 10.5.2.


After trying all the different "fixes" in the Leopard/network related threads with no avail, I tried booting my laptop into Tiger (10.4.11) installed on an external HDD. Voila, wireless file transfer speed is fast at around 8MB/sec (obviously using N). I did a fresh install of 10.5, and the speed immediately dropped down to 1-2MB/sec, although not necessarily stalling. Then, updating to 10.5.2 slowed it down more, and now the transfers will sooner or later almost completely stall.


Again, I tried all the suggested remedies (use b/g Only mode, adjust RTS/Fragmentation thresholds, use WEP instead of WPA, delete all the Network Services in System Preferences -> Network, etc., etc.). Nothing helps. I tried swapping the router to an older Netgear (802.11g/b), and it's the same deal, so it's not a router issue.


A definite characteristic is that the transfer seems to stall after a certain period of sustained transferring; i.e., this will usually only happen when transferring large files (>200MB). If I were to download a folder with 600 JPEG files @ 1MB each, there won't be a problem, and the transfer rate will be pretty fast (although not as fast as under Tiger @ 7-8MB/sec), and it won't stall. It's only when I try to transfer big video files, etc., that this problem occurs.



If you are having similar issues, please share your experiences, suggest remedies, offer insights. I will try to answer any question you may have and that I may have missed to address.


PLEASE: if your symptoms are different from what's listed up there, please try to refrain from posting here, unless you are absolutely certain that the issues are related. Thanks.