I don't believe it will work but it won't hurt either to try. The 6400 MB needs 3.3 volts which the 5200 doesn't supply. The 6500 MB will work though as the MB has the built-in circuitry to convert 5volt to 3.3.
You could add a 3.3 volt regulator to take care of that or just pick up a 6500 mb
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