Currently I have an i5 2500k CPU, with a Gtx Nvidia 970 superclocked. Obviously there is a bottleneck here and I need to overclock my CPU. Unfortunately I have a stock cooler heatsink on my CPU, so it is very hard to remove and cannot be overclocked. I just need to know if I can buy a cooler that will allow me to overclock to 4.4GHz or 4.5 without removing the heatsink, although if that is not possible, feel free to suggest coolers where I would need to remove the heatsink. Sorry if this is worded badly, wrote on phone in a rush. Cheers.