This paper focuses on low complexity architectures for check node processing in Non-Binary LDPC decoders. To be specific, we focus on Extended Min-Sum decoders and consider the state-of-the-art Forward-Backward and Syndrome-Based approaches. We recall the presorting technique that allows for significant complexity reduction at the Elementary Check Node level. The Extended-Forward architecture is then presented as an original new architecture for efficient syndrome calculation. These advances lead to a new architecture for check node processing with reduced area. As an example, we provide implementation results over GF(64) and code rate 5/6 showing complexity reduction by a factor of up to 2.6.