so i'm facing this weird issue, when electricity goes out, my pc restarts even if it's connected to ups, to fix this issue o upgraded the ups/inverter from 650w to 900w output connected with 150ah tubular battery. as i thought the inverter/ups probably can't supply enough power but i was wrong. i switched off the main supply and tested pc at max load and pc did not shut down even once and ran just fine. so i wonder could it be my psu? unable to handle sudden power cut (antec neo eco 550w) after doing some research on google i found it had old topology.
note: pc does not restarts due to power cut when sitting on ideal only when i'm gaming.