"Planescape: Torment" extremely slow

Hi all,

Recently I found an old DVD of “Planescape: Torment” for Windows.
I managed to install it through Lutris and Wine along with 1.1 patch, ITP translation, WideScreen mod and UI mod (by the way I also did some installation scripts for Lutris about it).
All the installations were successful, but unfortunately the game is unplayable because is too slow and laggy.
I tried to play it step by step between the patches/mods installations in order to catch the problematic piece, but it is always the same: extremely slow.
I modified torment.ini according to some online guides in order to achieve performance but to no avail.
I tried also to intall PT with PlayOnLinux with the same identical result: extremely slow.
I tried even to play it with GemRB: the game play nicely but it get an error just after the character creation, so I know the game is able to play smooth on my machine.
It is clear to me that this is not a Lutris issue. I believe that I am missing to modify some Wine or game configuration that will let me achieve performance to play smooth.
I am using Debian bullseye/sid 64bit, Lutris 0.5.5 , inside Lutris I use Wine 5.4 64bit, my CPU is AMD FX8350, 16GB RAM, GPU Nvidia GTX950 with nvidia drivers 440.64.
I hope the description of the problem is clear.


I forgot to mention that my DE is KDE.