You are not correct (at least not 100%). As I noted earlier, the flickering does appear even if you unplug the power.
Are you sure? 3 other people besides me said the problem goes away if they disconnect the extra power. Is your flickering even lessened when you remove it? Are you sure your refresh rate is higher than 75Hz when you're testing this?
If it doesn't get worse when you move the mouse around (try that in a menu or something) then you probably don't have the same issue we do??