Cooling Your Computer: Air Cooling vs Water Cooling
I get asked every now and then about what sort of cooling someone should use for their computer. And like much of the time, my answer is "it depends on a few things".
There are two different general methods of cooling a computer, air and water (we'll ignore liquid nitrogen, liquid helium, and phase-change cooling).
Air cooling is found in the vast majority of computers. Air cooling involves a cold plate, a heat sink, and a fan.
The heat source (we'll go with a CPU to make it easy) generates heat rapidly, and the cold plate sits on top to conduct the heat away from the source.
Cold plates are typically made of copper, due to the high thermal conductivity of copper.
The heat energy moves from the cold plate, through the heat pipes (sticks of copper), and into the heat sink.
From there, the heat sink (think of it as a bunch of thin metal plates) transfers the heat energy from the heat pipes to the plates/fins, and the fan provides the airflow to move the heat energy out of the case.
The case fans assist this, providing stable intake and exhaust airflow.
One very important thing to note. If the main fan on the air cooler fails, the heat sink still works (just a piece of metal), and the case fans can (in theory) provide emergency airflow to the heat sink.
While I don't recommend doing a heavy render with the main fail offline, the case fans can give you enough airflow to remain stable, and order a replacement main fan.
Water cooling however, uses water to transfer the heat energy, instead of copper pipes. Water has a very high specific heat, and can thus carry a significant amount of heat per unit.
For this reason, water cooling is more capable than air cooling.
Water cooling still uses the same general concept, but replaces the heat sink with a radiator (with fans). Just the same as what you find in your car.
When Air Cooling Wins
Before you run off and say broadly "water cooling is better than air cooling", there's another key element I haven't mentioned yet.
The number of heat-sink towers (and associated fans), as well as the number of fins/tower, and the overall design of the air cooler, plays directly into the cooling capacity of the unit.
A single-tower/single-fan $30 air cooler will "work", but it will be beaten by a single-tower/single-fan $40 water cooler.
Thusly, the $40 water cooler will be beaten by a high-end single-tower/single-fan $60 air cooler.
When Water Cooling is Bad
To a point I made above about the fan failing...the water cooler has one component that can potentially bring down your system. The pump.
If the pump fails, there's no flow. If there's no flow, the water can't move the heat energy from the source to the radiator.
Generally, this results in an automatic system shutdown in about 8 seconds, due to the CPU temperature rapidly rising to TJ max.
However, most modern liquid cooling solutions made by Corsair, NZXT, EVGA, Cooler Master, etc...have lengthy manufacturer warranties.
NZXT warranties their high-end water coolers for up to 7 years, they're that confident in the operational status of their product.
Your Use Case
That being said, water cooling is mainly used for several things; cleaner visuals inside (no massive air cooler) and lower temperatures. The former is a personal thing, the latter is geared towards enthusiasts and overclockers.
If you have no intention of overclocking, don't care about how it looks inside, and prefer long-term reliability over temps and noise, then go air cooling. Noctua makes the best air coolers in the world, and some of their big coolers are absolutely death-quiet.
If you aren't worried about a potential pump failure (if your PC isn't a mission-critical workstation), want a cleaner look inside, and would prefer a quieter system, then water cooling is a great option.
Ultimately, it comes down to what you're using your computer for, and what you value most in cooling. If you aren't sure what sort of cooling to get for your computer, we're happy to help figure out what works best for your system.