This 2.2 kg 1000W BeQuiet BN213 ATX power supply is able to provide 12V 83A (no typo. Eighty-three.), which is around 1000 W.
This huge PS900W (60V15A 30V30A 15V60A) bench power supply weighs 5 kg already, reaches 900 W, but is significantly larger.
This ~2.4kg PS-3010DF variable laboratory SMPS has 0–30V with up to 10A, which maxes out at 300W. It's housing is significantly larger than the 1000W ATX power supply.
This 230W 19.5V 11.8A laptop power supply is significantly more compact, weighs lighter and does not require any external passive/active cooling (heatsink or fan):
All of them are switching-mode power supplies.
How come the PC and laptop power supplies deliver much higher performances per same volume? What are the technical reasons?
Is it because the bench power supplies have a variable, adjustable output voltage while the PC/laptop power supplies deliver a fixed voltage?
But most PC/laptop power supplies usually have a current control mode when voltage controlled is no longer possible due to overcurrent. (also known as “current limiting”)
Is it maybe because of voltage ripple filtering or something similar?