I built my PC back in 2019. I am still using the same CPU : i7 8700k. I have upgraded my GPU to an rtx 3070. I play only GPU heavy games in 4k usually with DLSS. I’m able to run most games in an acceptable framerate, 50-60fps. I would say my frame times could be better tho. I dont run any CPU heavy applications, but i have noticed that with these latest AAA games it takes forever to compile the shaders. My CPU is pretty outdated at this point, and I’m wondering if it would even be worth upgrading considering my use case and that I am mostly happy with my gaming performance. Oh and I run Linux if that makes a difference.
Upgrading your CPU should help a decent bit with average percents, but the 1% and 0.1% lows should be WAY better.
I had a GTX 1080 at 4k and going from a Ryzen 1800x to 3700x to 5800x3D all saw pretty huge improvements in the lows. Average still saw some gains here and there. You should see a LOT more gains than me.
Keep in mind you’re not always GPU or CPU bound. Depending on what’s going on it could flip flop around.