Not really a bug, more a question, and probably something that should be addressed at the driver level.
I just enabled hardware acceleration in firefox using this, and while it works great I'm seeing a significant increase in power usage.
Using a AMD 3700x & Nvidia 3080 with 470.103.01 drivers, watching one 1080p h264 stream on twitch without hardware acceleration I'm seeing about 120W total consumption as measured by the PSU. Whereof ~46W is used by GPU:
# gpu pwr gtemp mtemp sm mem enc dec mclk pclk pviol tviol fb bar1 sbecc dbecc pci rxpci txpci
# Idx W C C % % % % MHz MHz % bool MB MB errs errs errs MB/s MB/s
0 46 45 - 28 19 0 0 810 510 0 0 1178 8 - - 0 318 154
0 46 45 - 27 17 0 0 810 510 0 0 1178 8 - - 0 170 144
0 46 45 - 28 19 0 0 810 525 0 0 1178 8 - - 0 170 152
0 46 45 - 23 17 0 0 810 525 0 0 1178 8 - - 0 169 142
0 46 45 - 25 17 0 0 810 510 0 0 1178 8 - - 0 169 144
0 46 45 - 24 17 0 0 810 510 0 0 1178 8 - - 0 178 155
Activating hardware acceleration, the power usage jumps to around 176-180W, all of which goes to the GPU:
# gpu pwr gtemp mtemp sm mem enc dec mclk pclk pviol tviol fb bar1 sbecc dbecc pci rxpci txpci
# Idx W C C % % % % MHz MHz % bool MB MB errs errs errs MB/s MB/s
0 111 48 - 11 3 0 5 9251 1785 0 0 1612 11 - - 0 131 255
0 111 48 - 10 2 0 5 9251 1785 0 0 1612 11 - - 0 132 242
0 110 48 - 11 3 0 5 9251 1785 0 0 1612 11 - - 0 19 127
0 111 48 - 11 3 0 5 9251 1785 0 0 1612 11 - - 0 7 130
0 109 47 - 6 1 0 5 9251 1785 0 0 1610 11 - - 0 0 140
0 108 47 - 5 1 0 5 9251 1785 0 0 1610 11 - - 0 3 127
0 108 47 - 5 1 0 5 9251 1785 0 0 1610 11 - - 0 10 127
Even if decoder usage is only 5% it never drops below 9251MHz memclock and 1785MHz GPU clock. Is this something that can be addressed at this level, or is it something that has to be done by the nvidia drivers?