Wifi is terribly slow (between 1Mbps and 15Mbps) on my 2011 Macbook Pro running High Sierra. On all other devices, iPad, iPhone, iMac, PC it is above 80Mbps. Ethernet is slow as well. Sometimes I hit spikes of around 50Mbps for a couple of minutes, but I don't know what triggers it.

It doesn't seem to happen if I connect to my phone's personal hotspot. Both phone and Macbook come in around 30-35Mbps, although I didn't test it for long enough to see if it's just a spike as well.

I tried everything in the last couple of days:

  • removing wifi network from preferred networks
  • renewed DHCP lease
  • fiddling with router settings and channels
  • connecting to 5Ghz and 2Ghz networks
  • resetting network settings by deleting network files from Library/Preferences/SystemConfiguration
  • SMC reset
  • NVRAM reset
  • scanning for malware
  • reinstalling OSX
  • installing El Capitan from the Time Machine backup of my iMac
  • turning off Bluetooth

Any other ideas that might help? Or is it faulty hardware?

  • UPDATE: I connected to another WiFi, different router, and it spiked again. It was speedy for about 10 minutes, after which it slowed down again. Aug 27, 2018 at 9:46
  • Hi Illes, welcome to Ask Different. You write Ethernet is slow as well. Sometimes I hit spikes of around 50Mbps for a couple of minutes, but I don't know what triggers it. That last sentence refers to Ethernet or Wi-Fi? Is your wireless router an Airport Express/Extreme? Have you followed the steps explained here: support.apple.com/en-us/HT202663 to troubleshoot your Wi-Fi issues?
    – jaume
    Aug 27, 2018 at 10:06
  • @jaume every network I connect to, ethernet or wifi, works well for 10minutes, after which it goes slow. And yes, I did also run diagnostics and got nothing Aug 27, 2018 at 10:11
  • Is your wireless router an Airport Express/Extreme? I had network problems (slow speed, connection drops) with my MBP 2011 when connecting to an AE until I changed its Wi-Fi settings...
    – jaume
    Aug 28, 2018 at 5:21

2 Answers 2


Seems the problem was hardware related. Something got stuck in my ventillator which made it stop.

When the laptop overheated after 10-15 minutes it underclocked all hardware, making the internet run slow.


I'm experiencing the issues with my MBP 13' (Late 2011) machine. It was not always the case. Although I'm running El Capitan and considering upgrading to High Sierra.

After some research and asking round. I've been told to change my HDD to an SSD and also upgrade my RAM (which is 4GB) to 8GB. Apparently Sierra which is a version lower than the one mentioned performs better on SSD and presume this would be the same for High Sierra. I've been reading reviews with users with a similar setup like you. They had seen some changes in terms of PERFORMANCE after switching to SSD. Hope it helps.


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