If EIST is enabled, the CPU will downclock to 800 MHz. The VID is dependent on frequency, so at 800 MHz the VID is likely 0.7V. Adaptive mode supplies Vcore equal to VID at default and lower freqs (depending on load) and additional voltage when overclocked. So that explains why adaptive is giving you 0.7V even with C states off, because the freq/VID is calling for it. What you lose out on in that configuration is the very low/zero sleep state voltages.
On the other hand, running in manual with C states on, you lose out on the downclocked 0.7V condition, but you instead get the very low/zero sleep voltage condition. Which is better is up for discussion.