If I remember correctly those Athlon II X3s topped out round 3.6-3.7 or so, regardless of voltages. Couple things to think about: your motherboard might be having problems running that high of a bus frequency (240). Also, since that frequency also overclocks your RAM, you may want to look through your memory menus to find what we used to call your "divider" to drop your memory speed back down. Running your motherboard at 240 may be pushing your RAM faster than it can handle. Try that, and if it works then you can look at dropping some of those voltages. 1.55v may be pushing your heat wall. My personal rule of them is to always stay under 1.5v. Yet another thing to consider: your NB clock and HT link both want to operate in a certain range in relation to your processor speed. Like your RAM, you can find a menu that will let you run your NB and HT link on a divider to drop them down a little bit. Consider this: Right now I'm running 4.0 on my 1090t (19.5 x 205) and my HT link is 2460mhz while my NB frequency is 2665mhz. You'll probably want to drop one or both of yours down a little bit to find stability at 3.6ghz.
AMDs overclock differently than Intels. It's not just pushing up your bus speed and adding voltage. Everything meshes together and adjusting one thing here requires adjusting another thing over there which then requires adjusting this other thing. It can be frustrating, but it's rewarding when it all comes together.
Another piece of advice. Start over and shoot for rock-solid stable at 3.4ghz before going any higher.
