Q: Slow Wifi on iPhone 6 Plus

Seeing same issue on an iPhone 6 (not plus).  Not having the same problem on either an iPad Mini Retina or my old iPhone 5 on the same wifi networks, both on iOS 8.  Using the Ookla Speedtest app on each of them.

I am experiencing the exact same issue. Doing a network settings reset only works for about 5 minutes then it slows to a crawl again. Also resetting my router would work for 5 minutes as well. I'm in the midst of troubleshooting with Apple support but one thing we found is that restoring to factory appeared to fix the problem completely. I restored from my iPhone 5s initially. When I restored from my 5s again after we did this test the problem came back. I cant abandon my backup so I need to figure out whats causing the issue.

I had the same issue and I seem to have corrected it.  Speeds are normal for my wifi now.  I will post the steps I took and hopefully someone can be helped by it.  Apple Care rep told me to reset network settings which frankly did nothing.  Here is what I did:

1.  Updated firmware on my router (D-Link).

2.  Reset all the settings and essentially created the Wifi network again.

3.  Switched from WEP password to WPA2 for encryption.

4.  Turned off DNS Relay in router settings.

5.  Restored the iPhone.

I don't know if one or all of these solved it, but I'm rocking and rolling now.  Hopefully this helps someone!  Good luck guys.

Same issues going on here with mine and my wife's iPhone 6.

After I activated both of our phones yesterday, I set both of them up as new phones. No restore from iCloud or iTunes backup.

At first, I didn't see any problems. Then, after about 5 minutes, wifi was beyond slow on both phones. I hopped off of wifi and onto LTE and the same slowness was present.

I rebooted my cable modem and router and that fixed the issue...for a couple minutes.

I then decided to reboot both phones, thinking it might be something with iOS. After doing that it fixed the issue again...for only a couple minutes.

No matter what I do, both of our iPhone 6's are beyond slow on wifi or LTE.

Using the Speedtest app, wifi download speeds are 0.30 Mbps. On LTE, just a tad over 1.0 Mbps.

Right after reboot though, wifi download speeds are 15.0+ Mbps. On LTE, close to 15.0 Mbps. As they should be.

Same issue with iPhone 6 plus model. On my old iPhone 5, the Cisco app test gives 7863 kbps, on my iPhone 6 plus, the same test done at the same time on the same wifi network gives 233,4 kbps ! What the **** is going on ?

OK, I decided to turn wifi off on my phone all together and reboot.

After reboot, LTE download speeds are not even at 2 Mbps.

This is straight BS

Changing my router from WEP to WAP2 did the trick for me.

Since my router is setup for WEP right now, I will change it over to WPA2 to see if that fixes the wifi issue.

Changing my router to WPA2 and having wifi turned off on my phone SHOULD NOT cause LTE download speeds to be below 2 Mbps though.

Changing encryption from WEP to WPA2(AES) did the trick for me as well!

Well, it appears my AT&T LTE issue has to do with my area right now. I left the house to go do some shopping and did some speed tests around town. Everywhere I was at I was getting 15+ Mbps down via LTE.

When I was about a mile away from home, I did another speed test and was only getting 2 Mbps down.

So, I can rule out my issue being with wifi and LTE.

I am going to setup WPA2 right now and see if that fixes the wifi issue.

My iPhone 5 was doing just fine on LTE in my area before I upgraded to the 6, so I don't know what is going on with that. I guess I will call AT&T to find out what the deal is.

The change from WEP to WPA2(AES) did the trick for me as well. Wifi is working as it should be now.

I will call AT&T after dinner to find out what is going on with their network in my area.

I have two new iPhone 6 and both have problems with the wifi .

The connection is permanently broken. the problem occurs on both ipones and at different routers .

with the iPad ios8 air and I have no problems in my wifi network .

sometimes the wifi connects again automatically , sometimes you have to multiply the password for the wifi to enter .

I don't think it's a WPA2 issue, I've always had my router set to WPA2-PSK [AES].  Done full resets of the router (R7000) and modem.  Occasionally the Wifi improves for a short time but then dies again.  While I don't fully trust either the Netgear router to be the culprit since it has had it's issues, I have an iPhone 5 and an iPad, both on iOS8, and a MacBook all able to connect on this network and get great Speedtest results, whereas the iPhone 6 has extremely slow connections on this network.

Same here, really glad that I found this post (iphone 6 not working with otherwise perfectly working Wifi).  Traded in iphone 5 worked perfectly with good Wifi speeds (iOS 7).  Brand new iphone 6 barely could do audio, incredibly slow Wifi.

I have stayed with WEP because of a legacy Roku radio box that cannot do WPA2.

For me, the only thing that worked was changing the router over to WPA2, Success!

Looks like for whatever reason, iOS8 and/or iphone 6s do not work with legacy WEP router settings.