A major difference is in sustained performance, not peak performance. Mobile CPUs often have cores these days that are comparable to desktop/server CPU cores bu

A major difference is in sustained performance, not peak performance. Mobile CPUs often have cores these days that are comparable to desktop/server CPU cores but they lack the cooling to sustain peak performance for very long. They're thermally throttled very rapidly. That being said you could take such a CPU and given it desktop-like power and cooling and it could perform like a desktop chip.