There's no heatsink in a laptop. All you get is a smallish piece of metal and a little bit of copper tubing attached that's somewhat in the path of airflow from the tiny fan. It's why laptop cpus generally don't run more than 25w± because they have no real cooling solution.
The OC ability on that laptop is a gimmick. A sales ploy to make it sound good, but is absolutely the worst possible idea for a cpu that can't keep itself cool without throttling. You'll get better and more consistent performance by returning the laptop to stock configuration and then undervolting as much as can remain stable. Lower temps = less opportunity to throttle the cpu/gpu clocks.