I personally have the ThermalRight Ultra-120 heatsink on my P5W DH right now and it has worked perfectly with no problems and excellent temps. Recently I picked up a 680i (reference model) and I am aware the 120 doesnt fit those because of little transistors (i think?) on the back of the board behind the CPU. As far as mounting the HSF I have also heard of problems with the tuniq tower just simply because of its size. The tuniq gets a few degrees lower but it nearly twice as wide.. with the fan on high but it is also loud, but it does come with a fan controller. Id do some research and make sure the tuniq can fit in your case. There are a few different factors so its all about what you are looking for, lowest temps? noise? size?