Speed & shader plugins for Maya

I’m using Maya to create artwork which is then exported using the Collada plugin from Feeling software. We’re comparing the performance of the shader plugin for Maya that ships with Feeling’s Collada to that of the CGFX plugin that was until recently made by NVidia (since acquired by Autodesk).

We’re finding that the NVidia is about twice as fast as Feeling’s version. Has anyone else experienced this?