So I just picked up the new 4690k and want to do some overclocking. My Motherboard is a micro-atx form factor so that could potentially cause a problem. I am stuck between the noctua nh-d15 and the nh-u14s. The overclock I am going for is 4.5 Ghz, and i want the cpu to be as cool as possible (preferably below 75 c). The nh-d15 will work in my system because my motherboard has two pci x16 slots so i can move the graphics card down if i need to. So my question is, should i go dual tower or single tower noctua heatsink.