Am now moved into a new flat with reinforced concrete walls - and the hammer drill was beaten. The holes were more than 2cm deep, but at least 2cm wide - no matter what weight I leaned against the wall.
Then came the hammer into play. Ok, new drill / chisel also. It does not require 1500 watts, the technology it comes to this: each well with a nominal diameter in 5 seconds. As in wood ...