Wifi is incredibly slow on OS X El Capitan

You and probably few people on this forum will want to hear what the fix for this is..... Its called Windows 10.

I bought a $300 Asus netbook with Atom processor and upgraded it to Windows 10 for my 12yr old son. That thing is so fast and reliable and has a fraction of the processor and storage that my Macs have its incredible. El Capitan killed my Mac Mini Late 2010 (8Gb with 1TB HDD) with and there are good and bad days on Macbook Air 2010. Wifi on the Air has been an on and off issue since Lion. I'm too scared to upgrade my Mac Mini Server.

iOS 9 gave my iPhone 5 the black screen bug when opening apps even native iOS apps like Settings. iOS 9 made my iPad2 very very slow. The Windows 10 Atom kills it in every respect far more pleasant to use.

To be fair, its very kind indeed of Apple to offer free upgrades but the upgrades should be optional and not of beta quality. I say they aren't optional because about this time every year, whether by "design" or "accident" the performance of my apple products suffer noticeably leaving upgrade the only realistic option.

But I'm off to the shop tomorrow to buy another Atom Netbook. Windows 10 is the fix. BTW the user interface is a gem. The only complaint is inability to set scrolling to "natural".

OK, so that was helpful... Not. This is for people trying to get help w/ Apple products, if you've got nothing to add except 'switch to windows' -- call us when you're wracked w/ spyware and viruses and your crappy $300 netbook is slow in 6 months. This forum is user to user help -- and you're not helping at all.

At some point I was thinking it was El Capitan causing the problem. This slow wifi problem started a few days ago after upgrading to El Capitan. I did all kinds of tricks to fix the slow wifi. However I noticed wifi in a Macmini with Mavericks was also slow. I activated the 5GHz option in my Airport Extreme and now all devices connect easily and have a fast wifi. You need to select the 5GHz network.

Hi. I did the above which seems to have messed with my email. It's all gone, settings not working. And safari still not any faster. Help!

Hi Graham,

FYI I did a full disk format and recovery of 10.11 then took the upgrade to 10.11.1 on the Mac Mini that I stupidly upgraded to El Capitan. (The other MM Server is still on Yosemite.) To my relief this fixed the wifi issue and other performance issues evidenced by beach balls everywhere from Preview, Mail, Safari, ...... etc.

But 10.11.1 broke compatibility with my Canon printer. Now neither Canon nor Fuji Xerox printers work. Apple don't seem to care about compatibility with other manufacturers products when they release upgrades. Every year since I switched to Mac I lose one printer or another for a couple of months while the manufacturer plays catchup with upgrades. El Capitan seems to have done them both in. Fuji Xerox announced they don't expect to release a new driver to fix Apple until Dec.

It a wondrous thing that Apple has to continuously write/update code that affects something as low level and generic as a printer driver or wifi. It makes one wonder if the guts of OS X look like spaghetti.

So its a good thing my "crappy" $300 ASUS eePC with Windows 10 is so ****** fast and reliable! No printer issues there.... (FYI another person on this forum called the ASUS crappy)

Good luck for your upgrade.

I've had the same issue with terribly slow wifi with a Macbook Air 2014 and a Macbook pro 2015.

The issue was so bad, that not even my local virtual box server loaded a website I'm developing and testing on it, a single load took over 30 seconds when the issue was affecting my MBP, after the fix, it's loading instantly, and so is every website, my rates on speedtest.net are perfect and in accordance to what my ISP is providing me with.

I tried several possible fixes, but what did the trick was the following:

1. Disable bluetooth
2. Open network preferences and delete every connection, once done, create a wifi connection.
3. Set DNS manually to openDNS
4. Disabled Wake for wifi on power settings

After doing this, I've been running perfectly on both laptops for over 4 hours now. I hope this helps others as this is definitely a bug in the network stack on El Capitan and Apple needs to pay attention to this ASAP, not emojis...

sorry to hear that happened to you, I upgraded to 10.11.1 and all my printers including my Canon and my Zebra are working fine.

What about your wifi?

My wifi seems the same as before updating to 10.11.1. Basically fine. What really helped my wifi was resetting my airport extreme to factory settings, unplugging airport extreme, unplugging cable modem for 1/2 hour, replugging cable modem, restarting airport extreme and reconfiguring as new. Now my biggest complaint is that my macbook wifi seems to vary between either 80mbs or 300+ mbs download and I don't understand why it defaults down to the 80 most of the time when it is apparently capable of 300+.

Also noticed when opening the Airport Utility the wireless RADIO settings changed

FROM:

802.11n only (5GHz) -- 802.11n only (2.4GHz)

TO

802.11n (5GHz) -- 802.11n (2.4GHz) AUTOMATIC

I put them back to 802.11n ONLY and this seems to fix the speed problem...

If you don't see these options in the RADIO menu do Option(Alt)-Click on te Radio menu.

After testing on both laptops, I'm getting much better results on 10.11.1, the MBA has 10.11 and even with the fix I posted, wifi drops from time to time, however, it's faster than before.

I have 15 inch MacBook Pro Early 2011 which is connected to a Air Port Express. The Air Port Express is connected via LAN to a Synology DiskStation. With Yosemite I'm getting transfer speed around 11 MB/s (thanks to the VERY fast Air Port Express LAN port). On El Cap it's not even 7 MB/s which makes it too slow for Time Machine Backups. I did a PRAM reset which did not help either. Any suggestions?

Found this link very useful to diagnose the problem.

http://osxdaily.com/2012/07/31/wi-fi-scanner-mac-os-x-mountain-lion/

Using advanced options in he wifi Menu

Resetting PRAM helped me too, thank you jubamad! Went from 1.2, to 19-21! Hopefully it sticks.