Low FPS on good pc

I've just bought a new graphic card to my PC. Now my setting looks like: i7 3770 RTX 2070 16Gb RAM ddr3 2400mHz Windows 10 64bit During every single game i start with about 150fps (which is still pretty low value imo) and it decreases to like 100 fps or sometimes even lower. I thought it's about CPU bottleneck but maybe you have some other ideas. ps. I can play other games with high rate of frames. I can even run RDR2 on ultra settings