Notes about the VSO file extension:
Incorrect file associations could be the result of underlying issues within your PC system. As such it is highly recommended to scan your PC for invalid registry entries, unused processes and other unfavourable system settings to identify slowdown issues.
The VSO file type is primarily associated with 'NVIDIA' by NVIDIA Corporation. A vertex shader is a small assembly-language program used by Direct-X programs. When enabled, it replaces the transform- and lighting-computations of the fixed-function pipeline for vertices. The .VSO file is a compiled version of an .NVV file.