That would mean (to mean) something like it doesn't have many functions, eg, it can't do square roots.
If your car has a low-powered engine, perhaps it can't go very fast or it can't go up a hill. The engine doesn't have much power.
"This laptop is energy efficient." High powered doesn't mean that something uses a lot of power. Quite frequently it is used for people, e.g. "a high-powered businessman/business woman. Or it can be a machine: "a high powered motorcycle". In that case the engine produces power by burning gas. A lot of times "low-powered" is used as the opposite of "high-powered" in a kind of humorous or joking way.