After trying reinstalling and applying fixes to the new P3D v2.3 a couple of times, I just rolled back to v2.2.
I know there are users reporting an improvement from the new version. Unfortunately I am not one of them.
Don’t know if the stutter issue was caused by my multi-monitors (probably not) or the clean install. Will try again to upgrade the system from v2.3 patches and see what will happen next.
For now, glad to have my system back to normal and get rid of those horrible stutters.