Well, I already understand that a FLEX source is a problem in terms of noise regardless of the brand of the source or its power.
The Silverstone 600w, second in reviews, seems to not trigger the fan until consumption of 200w/300w... I don't know if it's entirely true!
Silverstone also has another problem, which is that it is not modular and forces the user to have to keep all the cables inside the case, including cables for FLOPPY and Peripheral connectors, which serve absolutely no purpose other than being even more annoying. Anyway, do not understand!
For me, Flex fonts are not yet developed enough to use them.
The problem is that we buy cases for this price and then still have to invent something to fix a power supply!