Socks don't generate heat. All socks can do is retain the heat that is already there.
Hence, if you are in a cold situation, you should be sure your feet and the socks are warm when you put them on. If not, move your feet and toes around to try to generate some body heat.
I put on longer socks that cover my ankles and my feet feel a bit warmer. The fireplace on my TV playing Christmas Carols is giving me light but no warmth. Maybe I should light the real fireplace?