Did you install the newest Nvidia drivers?> that might solve the issue,

Rabbi_NASA wrote Did you install the newest Nvidia drivers?> that might solve the issue,

I uninstalled earlier drives using ddu ? And installed new ones and didn't seem to work.

Bump for possible reasons.

Few things that could be going wrong.

Temps for your GPU is getting way too hot and causing throttling. Monitor your GPU temps when in game and see where they're hitting. This isn't something that will always be your fault, some hardware can arrive dead on arrival, some can arrive in a shittier condition than others, it happens. If temps are hitting ridiculous high, I would say mid to high 90's would be a problem, especially if at 1080p. You may need to adjust the fan curve of your GPU in software such as MSI Afterburner or the ambient temperature in your room is too hot and you're going to figure out how to cool your room down so your PC in general isn't taking in that hot air flow and producing even more hot airflow.

If you use Nivida control panel for your games, make sure you turn off the recommended settings. Recommended settings will sometimes force upscale your resolution. When I was on the 970 card, CSGO would try to force upscale from 1440p to 2k, which would cause my game to have fluctuating FPS drops and in turn caused terrible stuttering. Make sure your games aren't being forced to take unnecessary settings. I know that sounds arbitrary considering you have a 1080 GPU, but if it's trying to force your game to 4k or god-forbid whatever reason higher, while giving you like 16x AA or anything like that, you'll be seeing the FPS drops.

Unlikely for this to happen if you're careful with your PC but also not completely out of the way. If you have any type of virus, malware, ect; that could be slowing down your PC when it comes to gaming. Do what you can to run a scan if none of the above have solved any issues with regards to your FPS drops.

Overall, first thing first, download software be that Speccy or MSI Afterburner + RivaTurner and monitor your system specs. GPU is the main focus but your CPU could also be hitting hot temps. Monitor them and make sure temps are within reason. If temps are and/or have always been within reasonable temps, load up Nvidia Control Panel and disable where Nvidia Control Panel will place settings what it thinks your PC can run on. You should be in control of the settings, not a software. If that wasn't enabled in the first place or if it still hasn't fixed the issue, run malware and virus scans to see if there is anything in your system causing problems. At that point if your problem(s) still isn't fixed, my last guess would be hardware issue/failure. From there it's checking one by one to try and figure out the problem or just trying to RMA everything and starting fresh. I would guess PSU first at that point as if the PSU is starting to fail, the CPU and GPU would then be "starving" on power, which in turn makes them not run to their full potential and causes the issues you're seeing now.