Your mistake/confusion is applying the nature of the unlimited hosting plan to hardware and other resources not in the hosting plan. I don't know how many more ways to explain it -- the thing that is unlimited is the hosting resources listed in the hosting plan and created by the provider, whether it be unlimited databases, unlimited email unlimited domains or unlimited diskspace. There is nothing in the hosting plan that promises unlimited cpu, ram, i/o, etc. The unlimited plan remains in the context of shared hosting. Never have I said or promised anything else.
98% of our sites can fit in your Plan A, the rest can fit in your Plan B with room to spare. We simply don't believe there is any reason to present hosting as a telescoping series of limited hosting plans of ever increasing resources (such as disk space) and prices. So we removed the quota limits for disk space and data transfer and call them unlimited (just like we do for email, databases, etc)
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