Also, keep in mind that unless you have an awesome cooler it probably will just reach the max temperature and auto throttle down.
Going from 4.8GHz to 5GHz is also a theoretical 4% increase that in reality you will likely never reach. Even if you managed 2% and were completely CPU bottlenecked in a game that would enable you to go from 50FPS to 51FPS.
Also the NOISE goes up quite a bit, but if you want to try go ahead. The worst you're likely to do is kill your CPU... though I strongly suggest you have a surge protector as a minimum protection just in case (your PSU has protection circuitry as well).
*On a final note, achieving a huge overclock for an hour, and sustaining it for weeks is a different story. Either the CPU or Motherboard could die in that case, or at least they're much more statistically likely to do so.