BUT AS HE EXPLAINED ONE AMP WAS MORE EFFECANT AT PUSHING THE 4 OHM LOAD THAN THE OTHER. SO HOW WOULD YOU TELL IF YOUR AMP IS UP TO THE TASK?

You have to look at its specifications. Usually the manufacturer give you rated power into at least both 8ohms and 4ohms, some also give 2ohms and 1ohm. The closer the amp can come to doubling its continuous power at each halving of impedance, the easier time it will have driving speakers with a lower impedance.

I just got to my hotel, so I will try to rewrite the reply I lost yesterday which explains this in more detail.