Between those, I'd take the CXm. There are no "reputable" reviews of any of the B5 series units but considering the history of all the B series models aside from the B2 units, I would not take the chance. The B3 series were extremely terrible, blowing up during testing and since we know EVGA has moved away from Super Flower for practically all of their budget units, the results have been underwhelming to say the least. The CXm isn't fantastic either, but it's at least better than the older CX units prior to 2017 and is not a series that has been demonstrated to have significant early failure issues or problems in being used in gaming systems. I will say though that given the price, if you actually NEED a 550w unit, get a 650w unit if you're going to go with a CX or CXm model. In fact, that would be wise when choosing a budget or mediocre power supply no matter what model it is.
Below you will find MY standard list of recommended power supplies and beyond that this thread is intended as a landing place for questions or discussions regarding specific units, platforms or related PSU tech, all of which are all welcome to be discussed here. If it's related to power supplies...
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