ThatVietGuy :
It's just the lowest end processor for portable devices (e.g. laptops).
https://www.lovemysurface.net/core-m3-vs-i5-vs-i7-processors-2017/
Whether it's "lowest end" depends on what you're doing with the laptop. The M3 is actually equivalent to a dual-core i7 (as your link shows). Just with a really low TDP.
The low TDP means it can't keep up with an i5 or even i3 on extended processing tasks (more than, say, 5 seconds). TDP actually refers to the cooling Intel says to connect to the CPU. The fan (or passive cooling - some M3 laptops are fanless) isn't able to keep it cool in extended processing, and it starts to thermal throttle.
But for short bursty tasks (not enough time for the CPU to heat up substantially), it will...