m364 (or above) has to be used if you are using Lion
However - m364 (and above) will also work with Snow Leopard.
The performance on a MacPro should be the same with either version - so long as you are using an Nvidia graphics card.
We run Snow Leopard still on our MacPros with m364 and get very good performance with an SSD and Quadro4000. (content dependant)

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