Q: 27" imac wifi problems (intermittant)

Apple called as requested. He had me go to Finder/hard drive/library/preferences/system configuration and delete the folder and restart. It's been working pretty well since. However, it's worked for a couple days in the past and then stopped again. Time will tell.

Same problem on my iMac 27", maybe its the design issue on its hardware. my Mac bought 4 weeks ago, and the internet sharing(via Airport WIFI) just work for one week.

Another consideration is the antenna. On your machine, your antenna is mounted behind the shiny Apple logo on the back of the iMac. That's because the slick aluminum case blocks wireless signals. You might try turning the computer slightly, or positioning your wifi base station differently to that the signal is better able to get through. While that's probably not the answer to everybody's troubles, you would be surprised how many times that does the trick. For us, turning the iMac just a few degrees solved all our issues with wifi dropouts. Hope that helps!

Exact same problem here. I sometimes has a 130 Transmit rate and suddenly around 40 and sometimes a total halt when copying files.
What I don't understand is, if the alu back is the problem, how come that it works fine sometime, and and not other times, without changing the position of either the Airport Express or the iMac?

Ah, thought it might be my setup, but apparently more people have this issue.
I received my (very first) iMac last Friday (the 27" i5), and the internet connection has been terrible. Granted the wireless router is not in the same room, but my €250 netbook with WinXP and my Xbox360 have no issues whatsoever and they're in the same room as the iMac.
Connection test (using Speedtest.net and a comparable dutch site) show really slow download speeds (below 1 Mbit), even though I have a 10Mbit connection.

I'd really like to see a solution to this problem.

For anyone still having this issue, I just now updated to OSX 10.6.3 and my connection speed has greatly improved. Probably not a coincidence

Add another to the list. Just fired it up today and have been on the second level of the house all day. Time Capsule Simultaneous Dual-Band is on the lower level. Have had great signal for 3 hours and now I can't even keep it connected to the network. My iPhone and MacBook Pro both show full signal and they have been on the same desk all afternoon. It appears that 10.6.3 doesn't solve this issue as I have it and the problem is just the same.

I also got a new 27" iMac for Christmas and have been going crazy with this wifi problem since then. I have had to go wired. I have a Belkin F5D8235-4 v2000. My wife has had her iMac 24" for just about a year without one problem with her Wifi connection. I had made the assumption that it had to be a hardware problem on the 27". But right before I had made a decision to make an appointment with Genius Bar I choose to experiment a little on the placement on the router. This had been the only thing I had not done. You see, my wife has her iMac on the other side of the house. 2k sq ft house. The router is sitting right behind my 27". You would think that I would have better connection. I removed all other electronics. Two printers, cordless phone, fax, etc. Placed router all over the room, still no fix. But believe it or not, I place the router just below the 27" under the desk and POW, solid connection. No packet loss. Very good stats. I have since put back all other equipment and still running great. I'm not sure if this will work for everyone, but I wanted to share my experience. See stats below:

2730 packets transmitted, 2730 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.564/1.582/214.662/5.177 ms

Trilobyte`s information about the location of the antenna seems to have helped me fix my problem.

Always intermittent to hopeless signal on imac 24" despite my macmini being fine in the same room but just now have removed plastic cover from the apple logo on the back of the imac and everything seems fine immediately.

Should have removed it before I know but didn`t see the significance.

Dutifully adding to the list. Brand new iMac 27in i5, brought home today. Set up, started downloading my regular apps and streaming some tunes. Suddenly the audio stream was choppy. I tried another browser, same problem.

I clicked on the wifi signal indicator in the menu bar and could watch the signal drop-- it would connect, then say searching for signal, then connect, etc.

I put my work computer, a 2007 macbook pro, on the same desk, right beside the new iMac, and it connected perfectly.

Anger.

I then ran speed test on both machines-- no question there's a wifi problem that's local to the iMac. The 2007 macbook pro transferred 8x faster than my brand new, expensive iMac.

FURY!

There are 3 other computers in this apartment, all connecting perfectly, and my new iMac, the only one that's in the same room, exactly opposite the transmitter, won't connect for more than a few seconds at a time before dropping out.

I'm running a cable now and the connection is super fast, but it's not a sustainable solution-- i can't have this cord running across this particular floor, or on ceiling, or around walls, or rearrange the entire room to accommodate this inexcusable wifi problem. Of all things Apple... connecting to the internet?? COME ON.

I have the same problem. 1 month old iMac 27 i5. Just updated to OS X 10.6.3. Wireless connection lot less stable and much, much slower than the 2-year-old aluminum Macbook. APPLE, PLEASE ADDRESS THIS ISSUE!

Hi, i have been having the same problem with my Mac, it was fine for 5 months then just stopped connecting. I was told by apple to change the way i connect to my modem from WEP to WPA. I have done this and it works. might be worth a try.

Having similar problems & have tried every fix possible. I don't think it's a hardware issue, rather a software issue. Apple had me do a clean install and the problems went away for a few months. I did an update & they came back. Will probably have to do it again, but that seems like pretty drastic solution & a pain to do.

I have the same problem with my 20" iMac. I'm convinced it's the iMac. Other macs sitting right next to it have no wifi issues at all. I've tried 5 different routers including 2 airports. The most obvious problems I have are the connection to an Airport Express with Airtunes dropping every few minutes.