This is a back-formation from {De'wI' SoSbor'a'} "main computer core". It has been generally *assumed* that *{SoSbor} is an independent word with the suffix {-'a'}, but we don't actually know this for a fact, do we? That is, it may be that {SoSbor'a'} is a word which just *happens to* end in something that looks like the suffix {-'a'} (similar to {bIQ'a'}). The fact that {De'wI' SoSbor'a'} is "main computer core" though does strongly suggest that {De'wI' SoSbor} would be a regular computer core, though.

(Also, the pun here is quite clearly {SoSbor} = "motherboard".)