"The laws of physics won't allow CPUs to go any faster than 2GHz"
Ah - dammit, the Intel vs. AMD showdown is nearly immediate then . *ROFL* ... as if

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As history has proven, we've broken quite a few "impossible to break" physical barriers & boundaries. Where there is a will, there's a way.
Point your foolishly deluded friend (is he?) towards the roadmaps (supposedly confidential) that are published on the on-line newspapers (the Register, Inquirer, etc.) and point him at the Intel one.
"There - 2GHz ... see? And I'll bet with you as well that by next year we'll be above that by a fair bit. What do you say?"

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Anyway - he's wrong, & needs some clear talking to about how ignorant he is, this much is certain

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