I had the same issue with a MagSafe 2012 MBPr (throttling when charging). It's just a lack of adequate heat dissipation in Apple's laptops, and with the USB-C o

I had the same issue with a MagSafe 2012 MBPr (throttling when charging). It's just a lack of adequate heat dissipation in Apple's laptops, and with the USB-C ones you suddenly get around it by plugging in on the right side where there aren't enough temperature sensors for it to properly throttle.