Wise statement. Realistically, you don't have to overclock much at all to get 720p. I seem to recall several testers of it were running 800Mhz. I personally run 500-900Mhz, but locking is a rather silly concept. Btw: even locking in general still leaves two levels, one of which is 0, or the resting state. But locking at a high rate means one rogue widget could suck your battery and turn your phone into a pocket warmer.
Keep in mind though, any time you install anything, you're taking a risk that it can cause instability. The less you know about it, the more likely it can screw things up. If you don't know what it does, or how it does it, best to stay away from it all together, because you probably don't need it anyway.
Now, about my black screen when changing res? Could that be a sign of underclocked cpu? Or may i miss any [ step | lib | thing ]?