Hi,
Yeah, I haven't tried it in the PC yet. Considering my experience with the first AX1600i (which failed in the computer after a month of use, fortunately without causing damage to any of the components), I thought it would be a good idea to double check before plugging a potentially faulty one into the computer. I think I will be returning this one (as you said, most PSUs are well under the 500ms PG threshold), so I'll look into getting an HX1500i instead. To be honest, I am halfway tempted to see if I can straight-up return the AX1600i and buy a new HX1500i instead of getting a refurbished one from the RMA.
Cheers!