Question why have my frames dropped dramatically?

[maxp963]

I finally got an upgrade on my GPU from a friend (GTX1660 super) and was pumped to have 100+ fps in CoD warzone and Coldwar zombies. up to 120! Unfortunately that only lasted about a week and now I get 50-70fps. I dont remember changing anything at all and its lasted this way for about a month. All my ingame settings are set to low and my fps is set to max at 170. My Nvidia settings are at 144hz so nothing is capping out. I have great internet hardwired in. I cant figure it out and its killing me.
My setup:
Operating System
Windows 10 Pro N 64-bit
CPU
AMD Ryzen 5
RAM
16.0GB
Motherboard
Micro-Star International Co. Ltd B450 TOMAHAWK MAX (MS-7C02) (AM4) 39 °C
Graphics
Pixio PXC273 (1920x1080@144Hz)
2047MB NVIDIA GeForce GTX 1660 SUPER (Gigabyte) 49 °C

Should I even be getting more than 70fps with this setup? My buddy says I should get around 110 120 and I WAS. for some reason didn't last long though.
PLEASE HELP!!

 

[MaddMann]

My guess is Nvidia Gefore "optimized" your settings. You may need to go into that and turn off automatic game settings. Things that will get you the desired frame rates are generally turning down unnecessary items like foliage and shadows.

 

[Brian Boru]

I agree with MaddMann.
If turning stuff down/off doesn't work:

Have you the latest Nvidia drivers, from Nvidia site?
If not, get them.
If you have them, try rolling back to an earlier version—I've seen a few complaints about recent versions causing some problems.