If you or your family and/or roomates are annoyed with a constantly humming GPU fan, why not consider liquid cooling your computer? Sure, simple air cooling is (was?) good enough to cool some small cars, but if you want something truly unique to add to your dual-GPU rig, few things will set it apart like a custom cooling system.
If you don’t know where to start, Carlos wrote in with his excellent set of instructions, linked above. Although there is definitely some ingenuity involved in this type of setup, it may not be quite as hard as you think. Most of the cooling components used are available off-the-shelf, so you won’t need “exotic” tools like a 3D printer or CNC router.
One of the more delicate parts of the operation is stripping the GPUs of their cooling fans and heat syncs. You’ll need to carefully strip the thermal paste off the GPU in order to properly apply the water blocks, which transfer cooling water in and out, taking the excess thermal energy with them.
According to the home page of this project, it took 12 hours to complete, as well as a couple months of research. Reportedly, the temperature dropped dramatically, and the constantly-running fans are nearly silent.