There is always a reason and 20W on a high end GPU Card is not unusual. If you search the web about this issue then you see that this is a general problem of NVIDIA. It depends on the screen etc etc etc…
That is true. My 1660 Ti idles at around the same. However, looking at both above outputs 25 - 35% idle GPU usage with no GPU thread active does not seem normal.
Mon Nov 15 19:12:55 2021
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 495.44 Driver Version: 495.44 CUDA Version: 11.5 |
|-------------------------------+----------------------+----------------------+
| GPU Name Persistence-M| Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util Compute M. |
| | | MIG M. |
|===============================+======================+======================|
| 0 NVIDIA GeForce ... Off | 00000000:07:00.0 On | N/A |
| N/A 49C P0 23W / N/A | 684MiB / 5936MiB | 1% Default |
| | | N/A |
+-------------------------------+----------------------+----------------------+
+-----------------------------------------------------------------------------+
| Processes: |
| GPU GI CI PID Type Process name GPU Memory |
| ID ID Usage |
|=============================================================================|
| 0 N/A N/A 2275 G /usr/lib/Xorg 263MiB |
| 0 N/A N/A 2340 G /usr/bin/gnome-shell 178MiB |
| 0 N/A N/A 3015 G ...AAAAAAAAA= --shared-files 11MiB |
| 0 N/A N/A 3811 G ...AAAAAAAAA= --shared-files 13MiB |
| 0 N/A N/A 3893 G telegram-desktop 1MiB |
| 0 N/A N/A 5978 G ...gl=desktop --shared-files 211MiB |
+-----------------------------------------------------------------------------+