You mean just to find your max speed? Well, since 1.85v and 2.8v won't hurt anything in the short term, I guess you could raise them both to that level and increase your bus speed until it's unstable, then back it down a little to stabilize it, then start lowering the vcore until it's unstable, then raise it just enough to stabilize, and finally lower your vRAM until it's unstable, then raise it just enough to stabilize. That way you can find your 1.) highest clock speed 2.) lowest acceptable CPU vCore at that clock speed 3.) lowest possible vRAM at that clock speed.
<font color=blue>You're posting in a forum with class. It may be third class, but it's still class!</font color=blue>