No it does not support the Phenom X4 955BE because it is a 125watt cpu. The best cpu it officially supports is a Phenom II X4 945 (HDX945WFK4DGM),3.0GHz,2048KB,95W,rev.C3 and you would have to be careful not to endup with the regular Phenom II X4 945BE Rev c2 that is a 125watt cpu that would not work in for motherboard. Hope this helps.
Source: http://www.asus.com/Motherboards/M2NPVVM/#support_CPU