Very few 4770K chips will be stable at 4.8GHz, and even then keeping them cool would be a problem.
For Haswell CPU's you need to be keeping the vcore below 1.2V, otherwise no amount of cooling will be enough. Learn to use the 'adaptive voltage offset' method in the boards UEFI. Which should allow you to get a good overclock with a low vcore.
Most 4770K chips should be able to goto 4.3GHz, mines will do 4.5Ghz with ease, well below 1.2V vcore. Taking it to 4.6Ghz requires a bit more voltage, and it starts to run quite hot.
PCie frequency should be locked at 100Mhz, going above this is very likely to damage any card, or on board chipset that relies on PCIe.
Set the BLCK clock to 100MHz, and be careful with the strapping frequencies.