bogus random entropy sources

From all accounts I've read, the entropy of the numbers derived from the C3's RNG hardware sucks rather badly, probably because there are so many sources of regular noise in a CPU that it's hard to stop some of them leaking in. The figures I've heard are *well* below 0.75, more like 0.4 if you're lucky. And IIRC the C3 doesn't bother to validate them either (certainly from the description in the whitepaper they don't), and because the pair of oscillators comprise a single system, if it breaks down or becomes coupled to something external you *also* cannot tell.