I googled ACE 750 watt power supplies and they are based on a older design so you have the equivalent to a 550 watt modern power supply.
It is based on a rather old and inefficient design(no DC-DC for the lower rails). As long as the system is not being overclocked it should have enough power as long as it delivers what it says.
If you MUST use it, do not treat it as much more than a 500-550 watt unit and it should be ok. With no experience with this brand I can not even say if it has built in safety in case of overload or overheating.
@ mbarnes86, Companies always recommend a larger power supply for the full system as well as to allow for cheaper units. I do not think my single gtx 670 system has taken over 350 watts under any...