Fortnite less fps despite better graphics card?

I upgraded my old gtx 1050ti to a Radeon rx 5700 xt but now I had to find out that I always have bigger fps drops in games that are also CPU lastg. In games the gpu lasting are like zmB. Modern Warfare or GTA5 I have none of these problems. I know that my i7-4790k bottlenecks this gpu, ways much wouldn't bother me either, because I want to switch to the r7 3800 xt later. According to reports on the Internet, however, Fortnite is said to have better results. I rebuilt Windows and reinstalled all drivers cleanly with the Driver deinstall utility. Now my question, can a CPU "break", so have less performance, my CPU is now 5 years old?

If the CPU gets very warm very often, this could be the case

So I used it boxed for 4 years, that will probably be the case, since it is also known as a very warm CPU, I have only had an AIO for about 1 year.