These screenshots are taken from the exact same (binary identical) video file opened in the exact same version of VLC (1.11) on two different machines. Both machines run Win7, and even though one is 64-bit, the VLC binary is 32-bit in both cases.
In other words, there are no significant differences that I can find. And yet, one of these is much less saturated than the other:
What can I do to stop VLC desaturating my videos like this?
P.S. As pointed out in the comments, one PC has an AMD card and the other is NVIDIA.