I have no comment on how good is your chip bro since I have never played with a 4570K before.
So far having some 4770K average chip is 4.5GHz @ 1.25v LinX stable. A golden CPU is doing as low as 1.2v at the same frequency.
Try playing with Load-line calibration in Digi+VRM option. It will control the way your CPU's idle/load vCore.

1) High performance RAM doesn't help CPU overclocking. Just that the higher RAM speed, the more stress the integrated memory controller (IMC) will get hence the more voltages you will have to pump to the processor to stabilize it.

2) The lower the temperature, the lower the vCore needed hence overclock ability is improved.

Get a better cooler bro for better overclocking. Stock cooler won't go that far 

I did some research and Noctua cooler seems to have a very good review. here's the site Noctua official site

I am using HTPC casing (Silverstone GD-06) and it has limited height and space for my cooler. Noctua has variety of choices for me. Quiet fan and efficient cooling (based on review).