thatsydneyguy :
OK. Thanks for clearing that up! I've got a couple of more questions if that's OK with you:
1. Is P67 Pro3 + i5 2500k combo better than Z77 Pro3 + i5 3570k? I've heard there are some problems with 3570k voltage and temps.
2. Will I be able to overclock to 4.4-4.6 using AsRock Z77 Pro3 + i5 3570k (Using Thermalright HR-02 Macho) without any hassle?
A lot of it depends on the luck of the draw... Each CPU chip is different. Some overclock very well and are just great chips, sometimes people get lemons.
If it were my machine and I were going to be doing a new build. I'd forgo Sandy and Ivy and get the New haswell chip. Here is my reasoning...
Sandy 2500k @ 4.5 = Ivy 3500k @ 4.2-3ish. So even thou the clock is lower on ivy it is able to perform the same amount of process's as the sandy chip at 4.5. Now you have haswell... Which is said to be about 5-10% more efficient than Ivy. So lets say 4.5 ivy = 4.4 Haswell... (the main upgrade in haswell was the integrated graphics)
But the main advantage you get with Haswell is the new socket. Which is going (or so the plans so far have said) to carry over to the next line of chips which will be named Broadwell. So... If you wanted you could do an upgrade without buying a new mobo etc to broadwell sometime next year when it comes out.
But, if your stuck with sandy or ivy. Go ivy. It oc's relatively well up to about 4.5 Ive seen people go a lot higher but again it depends on the specific chip, and cooling. You'll be able to achieve 4.4 ~ 4.5ish without issues and that would be about like getting 4.7 - 4.8ish on sandy.