"During the stress test the energy consumption increases to 239 watts thereby exceeding the rated output of the 230-watt power supply."
Is this conclusion based on comparing the same measurements? Does this take the efficiency of the power supply into account?
The picture here
www.notebookcheck.net/Our-Test-Criteria.15394.0.html#c2467883
looks like it is measuring the mains power supplied TO the power supply, not the output of the power supply. (There is a multiprong plug, not a jack that connects into the notebook.)
Power supplies are not 100% efficient.
A power supply rated wattage is the output power capability, not the input power consumed to produce that output.
So IF the power supply was 80% efficient, then 80% * 239w = 191.2w is being output by the power supply, well below the 230w capacity. (Power supplies may have less than peak efficiency at the edge of their capacity.)