I have a problem with my computer

I have a problem with my computer, I have an rtx 3060 and i5 10400f + 16gb of RAM, everything was fine before the war, now I'm in another country when my brother played at home, everything was fine, I moved the computer here, I noticed that the FPS in almost all games fell into 2-3 times, I looked, the video card dedicated GPU memory is 1.5 GB in the game at 4k from 12 GB, the use of total memory from 8 GB, around 0.1 in the game from 12 GB, also Bus inerface 1 3.0, from the maximum 16, s the processor is the same, I need your help.