TDP is also not a universal standard. The way Intel and AMD measure their TDP is totally different.
Also, as far as PSU efficiency is concerned on tower and desktop PC's is that there is a new PSU to MB standard, called EPS. It has 10pins and is completely 12V. This is to replace the old 24pin ATX PSU to MB standard.
These are much more efficient, especially at idle, since it's more efficient to convert to just one voltage and then let the MB convert to any other needed voltage.
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