Wifi is incredibly slow on OS X El Capitan

I've done more fiddling and it seems my Mac's WiFi is more sensitive to signal levels and WiFi congestion than my other devices. I live in a block of flats with fairly heavily congested spectrum. My other devices happily deliver full bandwidth but in the same location just a few meters from the access point the Mac has dropped its WiFi down to single digit Mb/s. I've already tweaked my WiFi to get the most out of it (picked the quietest channel) so there's nothing I can do about this but other users could see improvements if they optimise their coverage and/or channel selection as others have advised further up this thread. This could be an antenna sensitivity issue or a driver. Having never tested my Mac on Yosemite I've no idea if El Capitan made it worse or better. I'm not at all optimistic it'll be fixed and it's a shockingly poor performance from a premium product.

I was struggling and went through this and my house mate suggested I change my DNS settings which I had done before but to no avail. Either way his suggestion worked.
System Preferences > Network > Advanced > DNS > Add new DNS (8.8.8.8) > Remove old DNS.

Hope this works for everyone as before that fix this page took 10 minutes to load whereas now it took under 5 seconds.

Has Apple responded anywhere on this post? I am not happy. My modem/router combo is new enough that there are no firmware updates. I have tried every random suggestion I can find on this thread and the internet in general, and I am completely up to date in my Yosemite version. I have to turn wifi off and on ALL DAY long. I work via VPN connection frequently - this has become impossible. My first Mac, and I am full of regret.

I'm at a loss as to what to do/try next...?

Sadly yesterday's 10.11.3 didn't resolve the Blue-tooth > wifi issue.

I have 2 Apple Bluetooth mice, both effected the same.

An impossibly slow Bluetooth>WiFi connection seems to be a very well known El Capitan problem with lots of people complaining to Apple and lots of comments on websites - and of course suggestions but none of them seem to work for those affected. Why everyone isn't affected remains a mystery.

Lots of us hoped/prayed yesterday's 10.11.3 would fix this bug - but no.

It means that off-line I can use my Apple Blue-tooth mouse/mice but have to switch them off and revert to a clonky wired mouse for the Internet - the same with my Apple Blue-tooth keyboard. It's an absolute pain in the *ss.

I just "upgraded" to Capitan and my internet connection is ruined, every minute my internet connection stops for a minute, and starts streaming again a minute later. I did all the shut down and reboot stuff with the wifi and computer and it hasn't helped.

This is a serious waste of my time to research and try to fix this. I HATE you Apple.

same issue here - wifi so slow, tried all he solutions and still awful... Apple really need to resolve this...

So I had a similar problem ... fast ethernet, fast on my phone/tablet, but slow on my El Capitan 2011 Macbook Air over wifi. I fixed it by turning off my router's 5Ghz network and just used the 2.4Ghz one for everything. As soon as I did that, boom, my Macbook was connecting properly at 30Mbps (instead of about 5Mbps). Same approach might help you.

You could try switching off the 2.4Ghz network and keeping the 5Ghz one, but I have some 2.4Ghz devices only that I need to support. Plus I want the superior range of 2.4Ghz.

did u find any solution ?

Not yet, but then I haven't yet worked out how to try switching between 2.4 Ghz and 5Ghz on our [excellent] French Livebox router - assuming that is possible.

But this is a new - and I assume El Capitan - issue. Before El Capitan it was all absolutely fine. Since El Capitan there is a new, serious and infuriating Blue-tooth/Wi-Fi connectivity issue STILL not solved by the 10.11.3 El Capitan update

CN

PS I say our excellent French Livebox router - the whole of the French phone system is now basically internet-based through the LIvebox and works absolutely faultlessly as does our associated TV etc. So I hesitate to start fiddling with it - and we have windows PCs etc attached to it too. All I want is for my lap-top>Livebox WiFi connection to go back to working properly [or at all] - as it used to pre-El Capitan.

SUCCESS!

Like w1nt3rmut3 above, I found out how [pretty easy] to set up my French Livebox to run only on the 5Ghx network for my Macbook - and I've 100% lost the interference from Bluetooth for my Apple mouse - hooray!

That said, this was never any issue before El Capitan.

If you haven't resolved this yet, maeliz5412, I'd try the 5 Ghz v 2.4 Ghx router settings idea.

It worked for me - and I was going NUTS.

Good luck.

So it's interesting that you mention this. I get constant beachballing since upgrading to El Capitan. When I have GMAIL and Yahoo Mail open, Yahoo Mail actually tells you that there is no internet connection and suggest you go to system pref and use the diagnosis feature. By the time I do this the connection is re-established. I did just try having this computer use only 2.4ghz and the beachballing initially seemed to go away quicker. No other app actually tells you that the Internet connection has dropped. Finally at the bottom of gmail it says waiting for cache. At the bottom of Yahoo it says waiting for comet. Anyway, I'm so tired of trying to troubleshoot this.............................................

sdf007, my problem may be different in that it was my Bluetooth [so my Apple wireless mouse] that was interfering with my laptop>to>router connection. What solved this problem for me was disabling the 2.4 Ghz network and only having the 5Ghz network. @ 5Ghx the range is meant to be smaller but it seems fine for me at home.

It remains ridiculous that Apple STILL haven't resolved this widespread problem on El Capitan - and it was never ever like this before El Capitan and it seems to be driving lots of people mad.

charliebn its interesting that you mention this, I have a bluetooth enabled mouse. My Macbook air sits 12 inches from the router, and I rarely use it anywhere else in my house, so there is no need for 2.4. I just changed it to 5ghz only. If that doesn't work I may try an old wired mouse or trackball. I had no problems on yosemite.............

Hi sdf007. When my very-slow-hoplesss wifi problem first started [with El Capitan - NEVER before] I read somewhere about Bluetooth possibly interfering with the 2.4Ghz connection. I found that if I switched off Bluetooth my speed worked fine - as it always used to. If I used a wired [no Bluetooth] mouse it was fine.

So I disabled the 2.4Ghz circuit on my [French Livebox] Router], so keeping only 5Ghz. It 100% solved my problem.

But why don't Apple TELL everyone this - it's an absolute pain in the *ss!!