MacBook – 2015 Macbook Pro El Capitan – wifi drops when CPU active

macbook prowifi

When the CPU/GPU of my early 2015 13" Retina MBP running El Capitan 10.11.6 is under strain, the wifi drops.

I first noticed this whilst playing the web browser game diep.io in Chrome. When the game is running fairly CPU-intensively the wifi menu bar symbol turns to 'off' for a few seconds and then reconnects, hence booting me from the game. This happens intermittently – perhaps every 15 minutes. I thought it was related to the fan activating but I've observed it without fan too.

I've tested on 2 different wifi routers, both 2.4ghz, and with/without power cable – same results.

This is the only situation I've noticed the wifi dropping in – it doesn't drop randomly or suffer any other connectivity issues AFAIK.

Are there further tests I can run or solutions to try?

Update: some more tests

  • Chrome with hardware acceleration off: no wifi drops, but game doesn't run hot enough to activate the fan
  • Safari: Game doesn't work
  • Firefox with hardware acceleration: same as Chrome (no drops but no fan)

I'm thinking this may be simply a Chrome bug with hardware acceleration, but I'm worried the MBP hardware could be defective. Would testing with a non-browser-based CPU-intensive networked game or app be a good way to prove this?

Best Answer

In addition to the tests you've already run, and since your mainly concerned about your MBP's hardware, I'd also run Apple Diagnostics.

Run Apple Diagnostics

Follow the steps below to run Apple Diagnostics:

  1. Fully shut down your Mac
  2. Restart your Mac
  3. Immediately press the D key and keep it down until you see the Diagnostics screen appear
  4. Wait for Diagnostics to finish (this typically only takes a few minutes)
  5. Once complete, one of two things will appear on the screen:
    • a No issues found message
    • a brief description of any errors found plus further instructions
  6. If the diagnostics test does find errors, take a note of what they are

Note: If pressing and holding the D key at Step 3 doesn't work, start again at Step 1 and, at Step 3 press and hold both the OptionD keys instead. This will try and run diagnostics from the internet instead, so you will need to allow more time for it to complete.

Regardless, take a note of what happens and let me know how you went.

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