BUG: Mountain Lion kills wifi speed when using airplay or time capsule

One more test. I used my ATV2 to pull audio from my MBPro instead of pushing audio from my MBPro to my ATV2. No problems.

Same problem here. Airplay dies after streaming 2 mins. of music (or less).

PRAM reset doesn't work. SAC reset doesn't work. MTU manual set to 1200 doesn't work.

Feedback form submitted, with extensive detail. I referenced this thread, and also gave Apple a complete rundown of my experience with the problem and the troubleshooting I've done.

It does seem to only affect older (2007?) airport cards in Apple computers. My October 2010 MacBook Air has no problems whatsoever with Airplay or browser latency. I upgraded both machines to Mountain Lion during the last five days.

Maybe we'll get lucky and this will get fixed in 10.8.1 or .2.

Message was edited by: santranyc (typo correction and addition of one word)

I have the same problem on my MacBookPro3,1. WiFi Speed goes from 243 to 13 or 6 as soon as I use airplay to my Apple TV or a Time Machine backup starts.

Bug report submitted. Exact same problem on my MBP 3,1.

Mine is doing the exact same thing. I have a 2008 MacBookPro 3.1. It behaves the same way during a time machine back up over wifi. It doesn't really appear to affect my internet connection, but it does completely suck on the back up. I have to leave it open over night to back up the Mac. I haven't had a chance to test the Airplay yet as I don't use it much from my Mac. I did mess with Air Parrot since mine won't support mirroring without this add on. It behaved poorly and I think that this is why. I will test that too. My Wifi has gone down to a transmit rate of 6. Ah well, the bleeding edge is the cutting edge and WE BE BLEEDIN Boys!

We'll it seems to behave differently on the 2.4 GHz connection to the 5 GHZ one. My transmit rate bounces around from 39 to 19 to 13 .. well maybe not ..

It does seem to be backing up a little better and I do mean little on the 2.4GHz

I am also having the same issue on my 2007 Macbook Pro. FWIW, I've found that turning the wifi off, the immediately back on will fix the issue, but only for that backup.

I'm seeing the exact same thing with my mid-2007 Macbook Pro: Time Machine over Wifi is killing my wifi speed - on a 5GHz network the transmit rate is reduced to 6 and MCS index reduced to 0 during the TM backup. As soon as the TM backup finishes, then the Wifi signal goes back to 270+.

I'm really hanging out for 10.8.1!

i'm having the same issue with my 2-year old iMac. didn't notice the connection to time capsule but will pay more attention now to see if it only happens then (i often find myself canceling backups because it causes such a slowdown on my system anyway). Seems like i only get a few mins of wifi then it dies, but turning off/on wifi seems to help for another few mins.

Same problem here... It's just horrible. Networking run's fine on WIFI until Timemachine is starting. WIFI speeds drops to almost zero on my 802.11n network on my Mac. It's horrible! Never had this issue on Lion.

On ethernet it works fine. However, have no option to run a ethernet cable through the whole house.