Question Unstable FPS after SSD Upgrades on Laptop ?

Feb 7, 2021

I own a DELL 7567 Gaming Laptop. I have changed it's hard drive and SSD like below:

Old Disks:
120GB SanDisk X400 M.2,
1TB 5400RPM harddisk.

New Disks:
1TB Samsung 980 EVO Pro M.2,
2TB Samsung 860 EVO SATA

After changing them and reinstalling windows i have extreme fps drops in any game. Even without moving in the game.
I stay still looking at one point and my fps is like, 130 118 142 105 130 85 and so on. (changing extremely fast) without anything running in background.

I have checked with HWINFO that there is no power, thermal or any other throttling happening. CPU is running at max speed without dropping. CPU temp @ 65C GPU @ 57C

System Specs:
Dell 7567
CPU: intel i7 7700HQ (4c/8t) 2.8GHZ (3.4 turbo)
Ram: 16GB DDR4 2400mhz
GPU: nvidia 1050ti 4gb
OS: Windows 10 Pro - 20H2

UserBenchmark with turbo disabled:
( I am aware that my system does not support full speeds of Samsung 980 pro SSD)

What i have tried,
-Removing display drivers with DDU and install official Dell drivers
-Removing display drivers and use drivers provided by Intel and NVIDIA
-disable paging file
-Disabling full screen optimizations.
-Using Maximum performance setting on NVIDIA Control Panel
-Reinstall clean windows 10
-Install all windows updates
-Undervolting both CPU and GPU
-Using high or ultimate performance power plan
-Enabling/Disabling CPU Turbo mode.
-Disabling Xbox Game Bar and DVR
-Install games on both SSD's to check out
-Check Both SSD's for speed and benchmark with Samsung Magician
-Disabling/Enabling Game Mode in Windows
-All games are set to use NVIDIA GPU

i spent days to solve this issue but nothing seems to work.

i'd appreciate any help.