Hello there everyone I've been having this issue for a long time now (few months) and it's with my MacBookPro late 2013 15-inch, specs: Processor: 2.3 GHz Intel Core i7 Memory: 16 GB 1600 MHz DDR3 Graphics: Intel Iris Pro 1536 MB + NVIDIA GeForce GT 750M Storage: 500 GB SSD OS: El Capitan Version 10.11.2 Few months ago my old charger cable started tearing and the wires inside were being exposed day by day but the charger continued to work normally, but one day it suddenly stopped charging when I plugged it in, so what I did next was try to adjust the position of the cable to get to that "sweet spot" where it would actually start charging. And it worked for a while! after like a week or so of me doing this with my charger to get it to charge my Macbook it just stopped charging all together, now at the time I couldn't afford a new charger so I had to set my MacbookPro aside for a month or two. Few months later I bought a new charger and plugged it in and turned on the Macbook and it seemed to be working just fine so I set it aside to charge to 100% and came back later when it was fully charged, unplugged it and started using it, I browsed some websites and watched some youtube and everything seemed to be alright until the battery started running low...now here's the real problem, when I plugged in my macbook to the charger while using it the whole thing started heating up and everything started being glitchy and slow as **** and it became almost unusable, so I opened up the activity monitor app to take a look at what the problem might be; turns out that there's a process called "kernel_task" and it's taking up to 400-500% of my CPU resources..so I set it aside once more and left it alone to recharge to full battery and repeated the same process and I got the same result again, the thing was completely unusable So I started looking up online on what I should do and I found some solutions but none of them seemed to fix my issue or make it any better, so I decided to forget about the macbook for a while since I was on a vacation and they don't have an applestore where I am right now that I could take my macbook to so they would have it looked at. Now few days ago I got back from my vacation and decided to try and do a clean install of OSX El Capitan and see if that will make things any better (the issues I was having were on Yosemite) so I backed everything up and made a bootable USB of ElCap and wiped my SSD and installed ElCapitan. AND IT WORKED! for a while at least...I booted up my macbook for the first time after the clean installation and it was working perfectly! everything was super smooth whether the macbook was plugged in to the charger or not plugged in I was so happy..until I found out that the problem is still there..here's what the problem evolved into: my Macbook works perfectly fine at all times UNTIL I run anything even remotely resource demanding..I tried playing the Chess game that comes with OSX and things instantly went glitchy and laggy again, opened up activity monitor and CPU usable on kernel_task was 460%...this time the issue wasn't only occurring when the laptop is plugged in, it's happening all the time when I run any sort of medium-high usage app/task and this is especially weird because I used to play League of Legends with 90 fps on average before this problem came about, I used to play a lot of intense games and never experienced any sort of lagging or hiccups like the ones that I'm having right now...so please what should I do? I need this thing fixed asap I miss gaming on my Macbook but right now I can't even play browser games normally anymore...thank you in advance.