How far can i push this board?

Realistically, the limiting factor here is how high you can push the multiplier, the board should be able to handle anything you throw at it. Sure there are boards that will beat it, but for the price, you should at least see 4.5Ghz. But then again, it's up to the CPU.

The luck of the chip. That's all. The sandy bridges don't get hot, people with 5 ghz+ just have good chips..