We analyze the performance-power-energy balance of a conventional Intel Xeon multicore processor and two low-power architectures -an Intel Atom processor and a system with a quad-core ARM Cortex A9+NVIDIA Quadro 1000M- using a high performance implementation of Gauss-Jordan elimination (GJE) for matrix inversion. The blocked version of this algorithm employed in the experimental evaluation mostly comprises matrix-matrix products, so that the results from the evaluation carry beyond the simple matrix inversion and are representative for a wide variety of dense linear algebra operations/codes.