Im gonna make a guess that the CPU is more than capable. My guess is this.....that 40+ FPS "drop/low" in FPS is not indicative of the normal FPS performance while gaming?? meaning that 45fps is a Low in what is normally 60+ possibly even into the 70-80FPS? if this is the case, theres nothing to really worry about, as FPS drops can and will happen fro mtime to time, especially while fast movement is on screen ,or a large number of assets are on screen. i would only worry if it wasa constant sub 60 FPS Frame rate, and not while set to close to the highest settings.
remember its not only hardware of your system that can cause FPS perf drops, but also updates in game patches, or Drivers that arent as good as earlier ones. id personally run a drive fro nvidia that is fro maround when the 980ti was released, anything past that isnt likely going to have any + effect on Your GPU's perf, since they would have moved on to the newer models.
you could try running a system monitoring tool while gaming to see what if anything is maxing out during gameplay.....try GPUz. open the sensor tab, and leave it open while runnign 10-20 minutes of gaming then check out the readings
Come to think of it whatever you're running in the screenshot is probably going to provide just as much info As gpuz.
https://www..com/download/techpowerup-gpu-z/
I was just looking at the screenshot in your original post and I noticed that your GPU utilization is 50%.I may have been correct when I guessed that your temperatures are causing throttling you may want to look into that you could use MS I afterburner to set a custom fan profile or just manually put it at like 70% fan speed