@ poster
an amp doest provide a fixed power output, it varies according to the load u put on it.
E.g if u put ur 90rms speaker on an amp 150w at 4 ohms, as ur speakers will show bigger load i-e 6 ohms, they will extract less output arnd 100rms
But be sure to run them on hpf mode and set it at arnd 40hz, coz these are nice musical stereo speakers not drop low woofers