iMac Wifi Problems

Lion 7.2 was only recently release, give that a try if you haven't done it. I had the same problem when updated to Lion, but it’s now mostly gone with the latest update.

I've had this issue on the iMac also since buying it in June/July running Snow Leopard, (but never on 2 PCs, a MBP, 3 iPods and an iPad). Curiously watching around for solutions .

Went to 10.7.2 tonight, and waiting to see if this has an effect.

im on internet with ethernet but when i wake uo my imac it needs like 15 sec to find the internet conection, also my mouse disconects every now and then.
im on my new imac 21.5 mid 2011 and snow leo 10.6.8.
i think i ll go soon for lion to see wats hapening there

I don't know, if I had the same problem as described by you. My wifi connection was still active, but no packets went over the air anymore - it looked like wifi has been stalled. Turning wifi off and on made it work again for the next few minutes (iMac 2011, Snow Leopard and Lion).

The solution that worked for me, was to turn off the WPA2 CCMP option at my router and switch back to normal WPA2.

Note that I also have a MacBook late 2008 and an iPhone, that worked fine for years with these router settings. Only the new iMac made trouble.

Hope that helps,
Maruu

not sure if would work for you but...

my older imac (mid 2006 intel 2.0) was having issues loading pages extremely slow ect...

read somewere and works great....change/add dns server setting...system pref/network/(airport) advanced/+ add your isp's own dns server numbers or others (example google 8.8.8.8 and 8.8.4.4)

after i did this,pages load great...

I have had this problem since upgrading to Lion after I bought my 2011 iMac.

The problem with my Airport's wifi connection, however, also extends to my wife's iBook, which is running 10.5.8, I believe.