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I've never noticed any diminishing of power when a linking page has no public cache available. As long as the page is actually indexed and not penalized, that's all it takes. There are many good reasons for asking Google not to show a cached version of a page to the general public, especially including time-sensitive information.
That said, I never set out to specifically test this question - and Google can be full of surprises. However, I also can't see any logic behind changing the link's voting power for a reason like noarchive.