MacBook Air 2012 suddenly Super Slow/Lag

[romeao]

Hi after 6 hours of wait the installation had completed but it was still unbearably lagging, i did notice some graphics glitches here and there. I did try reinstalling on an external SSD after i removed the original but it was still same.
It seems to be some motherboard issue and have sent it over for inspection to a repair shop now.
i couldn't run the diagnostics as it was taking hours to finish.

 

[bzgnyc2]

Hi after 6 hours of wait the installation had completed but it was still unbearably lagging, i did notice some graphics glitches here and there. I did try reinstalling on an external SSD after i removed the original but it was still same.
It seems to be some motherboard issue and have sent it over for inspection to a repair shop now.
i couldn't run the diagnostics as it was taking hours to finish.

That's interesting -- usually when I see motherboard/CPU/etc issues, either the whole system doesn't work or it crashes frequently without warning. I am not aware of a limp along mode in these systems. Maybe if RAM is failing, it might be secretly running with less RAM than you think. Or if the fan, etc was failing it might end up in extreme thermal throttling.

In any case, would be curious to hear what your repair shop found. I am guessing if it is the motherboard, they're going to say it's not worth repairing but either way curious to hear the conclusion.

 

[real_mon2]

I would review the trackpad which contains numerous sensors. Start with a quick replacement of this piece. Then test again. If a sensor fails to be detected, the logic board will throttle the CPU speed. Common fault we have seen with macbooks in for repair.

 

[bzgnyc2]

I would review the trackpad which contains numerous sensors. Start with a quick replacement of this piece. Then test again. If a sensor fails to be detected, the logic board will throttle the CPU speed. Common fault we have seen with macbooks in for repair.

Thanks for sharing that. I never would have guess failing trackpad or similar sensors could throttle a CPU. I had assumed the CPU would only be throttled due to high heat/voltage/etc (or by the OS of course).