Newer updates often include enhanced graphics and compatibility layers that can be demanding. Older versions like 5.13.5.1001 are often "lighter" on system resources, leading to higher FPS on older CPUs.
The 5.13 version of BlueStacks introduced several "quality-of-life" improvements that remain relevant today: BlueStacks 5.13.5.1001 Older Versions for Windows
Starting with the 5.13 series, internal storage was increased to 128GB , allowing for more large-scale games and media files. internal storage was increased to 128GB