The two companies rate their cards differently when it comes to power. Nvidia uses TDP whereas AMD uses TBP (total board power). The AMD card is much more efficient with that taken into consideration.I think it is interesting as to how the Nvidia cards have been roasted (pun intended) for their advertised power draw and wattage requirements not to mention their heat output but the AMD cards are also in that same ballpark and the lower numbers are not always in favor of AMD.
Below are the advertised power draw figures in watts:
3070=220 watts, 6800= 250 watts
3080 320 watts, 6800xt= 300 watts
I do not see where there is enough difference to warrant a massive difference in the heat output and also if a persons PSU is running that close on headroom regardless of which brand competing card you choose according to the advertised power draw figures then either could well require a PSU upgrade.
Just thought this was interesting as these issues are made out to be such a negative for Nvidia but there seems to be no mention of these same issues concerning the AMD cards