Beside equalizing, Overtone GEQ applies harmonic enhancement processing. That is why Overtone GEQ is comparably CPU-heavy: it uses 7 harmonic enhancement modules, one for each EQ band. This generates complex harmonic coloration you will probably like a lot.
Since Overtone GEQ implements graphic equalizing by using an array of bell-shaped EQ bands--when you boost/cut adjacent bands--the actual boost or cut may go over the visual setting.
Overtone GEQ conforms to VST specification version 2.4, and so it is able to interface with audio host applications in full 64-bit floating point resolution (if supported by host application).