Comment by Telaneo

Might be helpful to get some perspective on this. Most cards idle in the 5-10 watt range, but there have been outliers, like the Intel A770 before the drivers were mostly fixed, which ran at 45 watts.[1] I believe there have been even more stupid incidents with cards combined with early drivers, where, if you just happened to have a multi-monitor setup running at two different resolutions, it would go up 70+ watts. Obviously, these are outlier situations probably caused by some optimisations being disabled while the drivers were developed, and never re-enabled before release. 20 watts and below should be easily achievable with pretty much any card, but it's easy to forget that this is still some work that should be done, and shouldn't be left to chance and happenstance.

[1] https://thinkcomputers.org/here-is-the-solution-for-high-idl...