Hi Edoardo,
The primary development platform for PixInsight is Linux. This means that the PixInsight core application and all modules are first developed and tested intensively on Linux, then everything is ported to macOS and Windows and tested again on these operating systems.
The Linux version of PixInsight provides the best user experience by far. It is basically 'the perfect one'. On macOS and Windows, I cannot achieve this goal for a number of reasons that are out of my control. The main reasons include problems with some development tools (mainly Qt on macOS) and problems with inconsistencies inherent to Windows (bad graphics drivers, defective OpenGL implementations, virus 'protection', malware, system 'utility' applications, and a myriad of wrong things that make the life of a complex multiplatform application quite difficult on Windows).
It is an ASUS notebook with a INTEL CORE DUO processor and 4 GB RAM + 1 GB Graphic RAM.
PixInsight should run on this machine, but it will put everything to the very limit, especially with version 1.8.5. I strongly recommend you try to upgrade your processor and RAM. Even a Core i5 will run much faster with 8 GB of RAM.