Thanks, seems there are several others with the same problem.

Same AP Extreme issue here
 

I've got the exact same problems with my 20" DuoCore. Pinging any site shows the same issue of fast then verrrry slow transfer of packets but nothing dropped. Speed tests at Speakeasy show it anywhere from 700 kbps to 1600 kbps, and that's on cable modem. I have a 17" imac G5 sitting right next to it that runs around 4000 kbps.

Apple customer support says nothing's wrong because I can connect to the internet and receive email. Hopefully Apple is aware of this problem and has a fix in short order.

Hi,
There is something definately wrong with the networking... the symptoms are exactly the same on the new 20" Intel iMac my partner just bought. Any update on fixes?
-j

Airport problems on Intel Mac Minis
 

Many people (including myself) had this problem. See link in the Apple support forums here.

My setup uses Airport Express as the Wireless Router (connected to the Cable modem) and was setup initially in 802.11g mode using WPA2 Personal security. My G4 iBook as well as another PC was able to connect without any problems and with full signal strength and were consistently showing expected connection speeds (> 3 Mbps).

However, the Intel Mac Mini (Solo) had connection dropouts as well as very slow connection speeds (< 300 Kbps).

After fiddling with all Airport Express settings, finally fixed the issue by changing the Airport Express (router) mode to 802.11b! After this change, the Mac Mini is not dropping any connections, signal is at full strength, and connection speed has jumped back to ~ 3 Mbps.

Maybe the driver/Airport H/w within the Intel Minis have a problem (firmware?) with 802.11g at this point.

Here's your solution to weird packet loss periodic ping times and generally slow wifi
 

The issue is not to do with g or b support (a happy coincidence for some), but rather the implmentation of IPv6

This is very new and clearly not there yet in OSX on the intels (most of the world is on IPv4 anyway)

This was doing my head in for a while, but now have a proper fast connection and no constant rebufferings when watching films or streaming iTunes.

To Solve:

Go to network preferences for your Airport, Select TCP/IP and the button Configure IPv6... Turn it off... et voila - a fast connection once more...

Hope you all see this as I was ready to reopen the dell or thinkpad - god forbid!

Cheers
Tarquin

Turned off IP6 - still facing issues in 802.11g mode
 

Turned off IPv6 as per the suggestion above. Still facing the same issues in 802.11g while connection remains fine in 802.11b mode. Maybe it's just my mini :confused:

Try opening your Airport Utility application located in Applications > Utilities. Choose the base station you want to configure and then under "Airport" click "wireless settings" and turn interference robustness on.

It worked for me.

I suddenly got this problem a week or two back. Could be when installing the latest Security Update - not sure. Anyway my connection was suddenly very unstable. And often it didn't work at all even though I had four bars in the Airport Icon.

Dude, that totally worked (or at least sped things up a bit). Why exactly would the IPv6 reduce bandwidth speed though?

KisMAC running a passive mode scan reveals this must be a driver bug
 

You can stablize your wireless connection while KisMAC (kismac-ng.org) is running your Airport Extreme card in passive mode. This shows that this issue is a software issue (driver) and not a hardware issue. This problem is also evident in the Bootcamp drivers for Windows running on these.

Do the following and you will see what I mean.

1. From a windows computer or any other stable connection on the same wireless network, run a continuous ping to the Macbook. You will most likely see the same erratic pings that I do.. 67ms, 114ms, 19ms, 45ms, (I have seen even up to 600ms, 650ms, 800ms, 200ms, etc.)
2. On the Macbook Pro, download and install KisMAC.
3. Run KisMAC and go to the menu bar, KisMAC --> Preferences --> Driver
4. Add the Apple Airport Extreme, Passive Mode driver and close the menu out.
5. take another look at your continuous ping.. still erratic.
6. Click Start Scan in KisMAC on the Macbook and enter an admin password to switch the card to Passive mode.
7. now look at your continous ping.. 1ms, 2ms, 1ms, 1ms, 2ms, 1ms etc.. Now it's stable.
8. Pickup your jaw..
9. Now click Stop Scan and the pings go back to being unstable.

I have duplicated this issue on all of the Macbooks (2009 models) I have touched. These are using Leopard and Snow Leopard. Same issue.

I have duplicated this issue on B networks, G networks, WPA and WPA2 PSK, WPA and WPA2 Enterprise (with 802.1x authentication using PEAP), Hidden and Broadcasting SSID's, different branded Access Points (Apple Airport Extreme, Sonicwall Sonicpoints, 2Wire).

The wireless adapter in this model apparently uses a broadcom based chipset that uses a software controlled MAC layer (Media Access Control). I suspect the issue lies here somewhere.

I have been trying to get these to integrate into an existing Active Directory network, and this wireless issue is causing so many headaches.. If this connection would be stable, I do not think we would have such a difficult time. But as it stands... We wait and search for a resolution.