Hehe ok ok last post b4 i go and buy my receiver =/

I was reading an article and it says that 40wpc is just as good as 100wpc, to notice a difference in volume you would have to have 500wpc. Is this true? Because i was looking and some Hamaron & Kardon receivers and they only pump out 40wpc. I thought i would need a high wattage to power my large floorstanding speakers? Thx