Very poor performance after upgrading HW

Hello,
after upgrading my pc to 1660 ti + i5 10300 warcraft 3 (the classic version, I don’t have reforged) is running at 5.7 fps constantly, making it impossible to play. I have tried making a shortcut and adding this extension (-windowmode fullscreen -graphicsapi Direct3D9) without any luck. Atm. I am reinstalling the game. I will update this post if it works. Thanks for help.
UPDATE: I have tried running the game on my second monitor and it works. I have no clue why. My main monitor is a 15.6" 1080p 120Hz monitor.

This is no longer supported? As far as I am aware Warcraft III only supports Direct3D11 on Windows and Metal on MacOS. Any other APIs that still exist are likely subject to removal.

I assume you meant a i5 10300H. Otherwise I am not sure what CPU you are using.

First download (not install) the latest graphic drivers from both Nvidia and Intel that are compatible with your system. Then use display driver uninstaller (third party tool) to completely remove the graphic drivers for both Nvidia and Intel. During this process turn off your internet connection to prevent Windows downloading new ones from its own servers. Now clean install both Nvidia and Intel graphic drivers, enabling your internet connection after the installation is done. Unless you have a need for it, avoid installing GeForce Experience as some of its features can potentially cause issues. This should assure both discrete and integrated GPUs are working as correctly as possible.

Now under Settings → System → Display → Graphic settings add Warcraft III. Make sure it is set to High performance (use Discrete GPU) mode under its options. This is to make sure Warcraft III does not accidently get run on the integrated GPU which is much lower performance than the discrete GPU.

Alright, I will give it a try and yes it is a i5 10300H. Thanks a lot.

Thank you for the update, Lamp! By chance, what’s the secondary monitor’s resolution and refresh rate? Could we also try checking out the DxDiag file. Copy and paste the text file created and paste it between two ~~~ like so:

~~~
DxDiag Here
~~~

If you have issues pasting here, use Pastebin and post the end of the link. (ie. 123456 for pastebin.com/123456)

If this is a laptop and the secondary display is an external display then it must be because the built-in display is using the integrated GPU while the external display uses the discrete GPU.

If this is a desktop then make sure that both displays are connected to the discrete GPU card. Even if the motherboard IO has a display connector do not use that as that is connected to the integrated GPU and not the discrete GPU so can cause applications difficulties using the high performance discrete GPU.