Green Flickering on Black Pixels - Macbook Pro 2011 (Auto Graphic Switching)

Question

So, I had a panic an hour or so ago because randomly my Macbook Pro 2011 screen decided to display flickering green on black pixels.

This looked quite bad on my desktop as it has so many dark colours:

After a frantic Google and Stack search, I found THIS that basically says to open up the Macbook, disconnect the screen cable, clean it with a can of air and reconnect.

I did this twice, but it didn't work for the most part.

I then went on to find THIS on this exchange, that suggests the first port of call is to disable "Automatic Graphics Switching" before trying anything else.

So that's what I did... I think...

I actually went into the Energy Preferences and ticked the box, so it looks like the image above...

It's worth mentioning, (and something I've only just realised), at the time, I had a couple of web browsers open, one with youtube playing, just as I opened a Word doc in Microsoft Word! I believe this is around when It happened. (Although I had just moved the Laptop back from another desk as I was cleaning too), Possible irrelevant but worth noting.

Anyway, could Word opening have caused the Macbook to enable/disable graphics switching some how?

So basically, my questions are, firstly, does it mean I've just enabled or disabled Automatic Graphics Switching? Secondly, why are the dark pixels flickering green? And thirdly, has it fixed the problem, or is there still a hardware problem somewhere?

Answer 1

This is related to the AMD Radeon discrete graphics card. It is a hardware issue.

I noticed it come up when plugging in an external monitor on my 2011 MacBook Pro 15" (as it forces the discrete graphics to be used at that time).

The only band-aid fix I was able to find was to force the use of the Intel integrated graphics over the AMD Radeon graphics card. I found a handy utility called GfxCardStatus to both show you what graphics card is in use, and also toggle the use of the Intel integrated graphics card. The utility is available at http://gfx.io

Unfortunately for me in my case, you can't use the integrated graphics card with an external display attached. But at least it gets rid of the green dots in some cases.

Answer 2

My machine: 2017 2.9 GHz Quad-Core Intel Core i7 Macbook Pro 15" 16gb 1TB Radeon Pro 560 4 GB, Intel HD Graphics 630 1536 MB; macOS Catalina 10.15.6

Ok I had this exact issue but it was with blue artifacts instead of green. I used your clues to solve the problem!

I noticed my issue was recent after a ICC color calibration with an X-Rite i1Display on my integrated Color LCD screen. I recalibrated two times and it eventually went away. Then it returned. I found this thread and used the gfx.io utility to control the current graphics card being used. I found the artifacting only showed up when the integrated Intel 630 was used. And I finally realized the issue was the ICC profile must be corrupt as I could literally switch between integrated and Radeon and the artifacts toggled with switching. Maybe it was calibrated while the switching was active and the profiles became corrupt, I'll never know.

So to fix, I used the gfx.io app to switch to Intel HD 630 graphics, then recalibrated the color ICC profile with i1Display Profiler software. The resulting new profile had no artifacting or corruption in display. Then tested the new ICC profile by switching between both Intel and Radeon cards, and no issues!

Hope this helps! Thought my graphics chip was going bad.

Answer 3

I just had this same thing occur on my iMac's display. I ended up chatting with a tech rep through the Apple Store app...and he recommended that I "Reset NVRAM"...so I did...and it fixed it. Hopefully it stays fixed and doesn't become a reoccurring thing. My iMac is almost 6 years old now, so I'm rather expecting stuff like this to be occurring more frequently going forward.

So, yeah...if anybody ends up here in this thread from a google search, try resetting the NVRAM as your first step in the troubleshooting process. It's a simple first step...and fortunately I had success with it.