Here is a recent post about getting near 5.0GHz, this is written by me
After 4.6, every chip starts to needs some serious vCore to get it going, it is breaking a 'Barrier' as it starts to get into 1GHz + from stock. Most chips will stop at about 4.5 - 4.60 due to it simply being too much. A 3770k will problably only need 1.20-1.30 to get to 4.5, if not less, but it will need 1.40-1.5+ to get over the 5.0 barrier.
At 1.45+ the CPU life starts to get shortened, this is due to extreme over-voltage. And the next obstacle is temperature, a 212Evo will get the CPU to 4.5 with reasonable temperatures, but after that the temperatures will rise quickly and you will need a cooler like a H80i, H100i or a Noctura NH-D14 to get near the 4.8-4.8 mark, but to get to 5.0, considering you got a good chip, you will most likely need a custom open-loop water cooler.
Ivy Bridge CPUs also have another thing limiting you, the IHS, or also know as the silver heatsink that is on the top part of the CPU, Intel made poor decision and filled the inside with thermal paste unlike the previous chips which used solder to unite the parts, changing it will let you get to about 4.6+ with much better temperatures as the thermal paste will simply not be good enough to get higher. The only option is delidding your CPU, this is a dangerous action and requires a very still hand, there have been many cases of the person pushing it too far and just make contact with the inside can kill you chip.
But you need a high quality PSU with a bit of headroom to get past 4.7, A 4.8GHz 3770k will pull about 120w depending on the amount of vCore used. That is a bit more than 20w more than the stock 99w, And after that it will only get more power hungry, it will probably pull near 130-145w at 5.0, that is almost 50% more than when we started off at 3.5 .
A good motherboard is also required, cheaper boards pack cheaper VRM's, these are the little capacitors/regulators that feed you chip with the voltage it needs, a better motherboard will require less volts to achieve a certain CPU speed, thus reducing temperatures. Cheaper VRM's tend to overheat and kill the board when the CPU is overvolted, you can see accounts of this happening with lower end MSI motherboards.
I hope you take the above into consideration and also, Sandy Bridge does not need delidding as it uses flux-less solder. But most importantly Every Chip Is Diffrent! Chips from the same batch will always be different, some may get over 4.9+ and some will struggle to hit 4.0, Good luck in making your decision.
Thanks to WR6133 and Twocables To Help me edit This
Sent From My Rooted Galaxy Ace II