Low GPU/CPU usage with low FPS

Hi guys, any advice what to do? 35-45 FPS while CPU and GPU usage is this low? Changing graphics makes almost no difference, only if I raise resolution scale to 150%, GPU load rises above 95%. Otherwise there is a slight change in loads when I switch between visual presets, but not in FPS. I have no problems in other games. When my FPS drop below 60, there is always CPU or GPU load at 98%, so there is a reason to drop. But not in Heat, whichj is just ridiculous. I don't know what to do. I tried a lot of guides like optimizing settings, tweaking Nvidia Control Panel, clearing Origin cache, repairing the game... Nothing worked. But it's even worse now. My game runs at 20-25 FPS on every preset. Low/Medium/High/Ultra make ABSOLUTELY no difference. Need to say I was able to run it at 45-55 FPS few weeks ago...