> 200 W pcu with 80% efficiency: 160 W. PCU with 95% efficiency: 190 W
That's not how efficiency is computed (in general, but especially in PSU).
The power rating (200W in your example) is what the PSU can provide to the system as DC power, the efficiency is the difference between AC input (wall-draw) and DC output.
An 80%-efficient 200W PSU will provide 200W internally but draw 250W from the wall-plug (and waste the extra 50W as heat).
If your 200W PSU maxes out at 160W it's not because it has 80% efficiency it's because it's a worthless piece of shit. You should throw it away as there's significant risk it will blow up (figuratively or literally) and/or catch on fire. Here's an article (in french but you can look at the pictures) checking out garbage PSU exhibiting that sort of behaviour: http://www.x86-secret.com/dossier-36-3000-Alimentation_Nonam... spoiler: shitty components, detonations and burnt smells.
That's not how efficiency is computed (in general, but especially in PSU).
The power rating (200W in your example) is what the PSU can provide to the system as DC power, the efficiency is the difference between AC input (wall-draw) and DC output.
An 80%-efficient 200W PSU will provide 200W internally but draw 250W from the wall-plug (and waste the extra 50W as heat).
If your 200W PSU maxes out at 160W it's not because it has 80% efficiency it's because it's a worthless piece of shit. You should throw it away as there's significant risk it will blow up (figuratively or literally) and/or catch on fire. Here's an article (in french but you can look at the pictures) checking out garbage PSU exhibiting that sort of behaviour: http://www.x86-secret.com/dossier-36-3000-Alimentation_Nonam... spoiler: shitty components, detonations and burnt smells.