the heatsink is the part of the cooling device that attaches to the cpu. usally grey or balck in color.the fan then screws on top of this to cool everything down, i idea being that the heat from cpu dissipates up the heatsink to the nice cool fan. I have a thermaltake case with 8 fans , so heat for me isnt a prob.However, u dont need to spend loads of cash on a new fan. I biggest prob is getting rid of the heat. What you need is one fan blowing in nice cool air, and one fan blowing air out. Therfore the fan on top of ure heatsink will have nice cool air to blow instead of warm air.