Stepped VS pure Sine wave output. Stepped bad for my MacPro??

[Anonymous user]

Just wondering if the stepped power output of the APC BACK UPS 1500 VA XS was safe to use with a MacPro and Cinema Display?

Message was edited by: hassiman

Message was edited by: hassiman

[BillP · Accepted solution]

some Mac customers experience a slight humming from their power supply when the UPS runs on battery. others work just fine.

you also need to make sure that the 1500VA Back UPS model (which can handle 865 watts) is sized correctly according to your power supply. you should find out the wattage in your power supply and multiply it by 1.5 if it is power factor corrected. if you don't and your power supply is a PFC. you can run into overload problems as well.