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Sorry I’m from Hong Kong and my English skills are very low I just bought a second hand MacBook Pro 15” 2011 Late i7 2.2 GHz from a Facebook user. Sadly, I found a problem with it. The system has a terrible lag, asked the seller immediately and he said he don’t know and was just helping his friend to sell it then he blocked me for any further dialog! I google searched looking for more information on this condition. Most of the results and instruction to try to fix the issue nothing helped. Here’s one link thats like my systems problem: https://discussions.apple.com/thread/822… Okay let’s back to help me. 1: CPU Load OVER 90%~100% when use 5~10 mins 2: When CPU OVERLOAD is on, EVERYTHING SLOW. But if I close the MacBook up about 30 secs then open it back, CPU Load is back to Normal, but 5~10 mins passed, it will back. 3: Computer fix shop found my Battery is not Original My MacBook is at the computer shop now and they tried to fix it about 1 week and they still have no idea. They changed my Original HDD to SSD, installed the newest MacOS, Changed the RAM, they found my Battery is not Original and it’s new! 5 Cycle count, they didn’t have an original battery to change it for test, so they think the Battery is not the point make the computer lag and they fully checked my MacBook only the Battery is not Original everything is Original works well. (Also the discussions apple link the last answer is Direct BATTERY is not ORIGINAL) [I tried to find his friend 2weeks and I writing this post he replied he changed the battery and upgraded the macOS to HIGH SIEERA in same time then he found this lag problem too so he wanna sold fast] 4: Keep CHARGING , CPU Load keep in Normal Keep Charging with 85W Apple Original Power Plug everything is well , but if I remove the power charge, CPU Load will Over 90% IMMEDIATELY 5: Reset SMC, PRAM, & Safe Boot didn’t help anything Please help.Thanks (I told the computer shop worker some repair problem I can’t do like: 1: Try to replace the Trackpad sensor {I found this from: Fan running at full speed, CPU throtled} But I don’t sure because the Fan is normal. 2: Try to downgrade to El Captain ————————————— Here is the test screenshot
CoCoNut 21% charging
CoCoNut 100% without charging
I just reboot about 2mins and TGPro status
lagging TGPro status
and the system background window (CPU System Load - User - Idle)
v this is my close up 30secs reopen capture v
If it runs flawlessly without battery plugged to the logic board you possibly have just a faulty battery, it can cause CPU throttling and full speed fans. Try and error is usually the essence of modular repairs but it requires parts available and they cost money. You won’t find an original battery in the market unless you go getting it replaced at an Apple authorized centre, but non original batteries should work fine too.
I really think you need to do some deeper diagnostics here! The very first is to run the onboard diagnostics. Boot up your system pressing the D key to get into it. Did any errors pop? If so what did you see. Reference: Mac startup key combinations I would also install a good thermal monitoring app like TG Pro it will allow you to visually see what the onboard thermal sensors are telling you. There are other sensors but often its one of these that leads us to the fault. Post a screenshot of the full main window (you may need to grow it a bit to get all of the sensors to be seen Adding images to an existing question Visual inspection popping off the bottom cover to look for staining and corrosion on the logic board. As this is a used system we don’t know if something was spilled or if the system sat in something. If possible I would also remove the logic board to inspect the other side both the uppercase and the hidden part of the logic board MacBook Pro 15" Unibody Late 2011 Logic Board Replacement. Post some pics of anything that looks off (sharp & big)
