[wtallis]

> It seems 4c requires .1v more through most of the clock speed range.

It doesn't look anything like a constant offset to me: https://pic2.zhimg.com/v2-3246ea92d494fffe1ea26f30bc9d9d79_b...

[WithinReason]

That seems like the same voltage at about 1 Ghz less clock, which makes sense.