My PSU tester shows low PG values for two new 1000W units, one from Corsair and one from MSI. The tester was purchased in 2017 and gives an in-range value of 180 for a known good Corsair 750W supply. Both MSI and Corsair tech support recommended returning the units. Should I keep buying new power supplies until I get one that tests good? New tester? Buy from someone other than Amazon? All insights and suggestions welcome.