Not to be too rude, but it sounds like some of you need to
read up on overclocking...
Basically, chip manufacturing is NOT an exact science - at least when it comes to clock speed. The rating on the chip is the recommended setting that the manufacturer is guaranteeing. It is usually much lower than what the chip will actually perform at. However, individual chips are not tested for the maximum rates, only that they perform at what they are supposed to. Therefore one chip that is rated at 528 Mhz may run at 700, 800, or even higher while another one rated at 528 may barely cap out at 600. The only way to know is to test it. Furthermore, running at higher rates also requires more power. You may get lucky and have a chip that can hit 900 or 1 Ghz, but it'll be draining your battery like nobody's business - and may even cause underlying calculation errors when processing. There's just no way to know.