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Why we don't have 128-bit CPUs
(www.xda-developers.com)
This is a most excellent place for technology news and articles.
I gave up trying to figure out what the "bitness" of CPUs were around the time the Atari Jaguar came out and people described it as 64 bit because it had 32 bit graphics chip plus a 32 bit sound chip.
It's been mostly marketing bollocks since forever.
The Jaguar lied with the truth, and I say this as someone who still owns one.