its the cheapest one, Zeus. Do I detect a hint of sarcasm here?
Sarcasm, no. There are legitimately power supplies that are really that bad. Some that either use a deceptive model number, or even outright lie about their wattage.
Power Supplies are a SAFETY item. They are guilty until proven innocent. You do not gamble your hardware on a substandard power supply.
Not having heard of Zeus as a PSU maker, I am going to assume they are bad - but what is the EXACT model number on it? If you can photograph the power specs label on the PSU, that would be very helpful.
Still, the first link in my sig takes you to a write-up that explains exactly what are good vs bad power supplies. That is a MUST READ on the topic.