Is Liquid Always Best?
The largest available coolers to fit most large cases are typically based on liquid thermal transfer, and the flexible hoses also allows some builders (depending on case design or modification) to take advantage of the cool intake air by mounting the radiator on the front panel. This method ejects CPU heat into the case, but the large volume of air passing through the radiator diminishes its effect on other components.
Top mounting is still the most common option though, and radiators placed there usually work best with the fans underneath, blowing upward. Yet a problem arises when the heat of an excessively hot graphics card is blown into the case below the radiator, as the warmer air is less effective at reducing coolant temperature. Planning ahead is key to the solution, as most high-end GPUs (graphics processors) are available in both internally and externally venting designs.
Concerns about graphics card heat being ejected through the top-panel radiator have been addressed in my own builds by using graphics cards that expel most of their heat through a rear-panel expansion slot, as seen in the silver card above. Yet graphics card reviewers frequently recommend dual-fan or triple-fan cards such as the black card above, focusing entirely on the improved graphics temperature-to-noise ratio without any concern for the impact that waste heat has on every component above the graphics card. Because I review both cases and CPU coolers, I consider graphics coolers that blow heat into the case to be defective.
The debate between graphics and processor priorities need not get heated however, as liquid cooling both the CPU and GPU is another option.
An alternative to liquid cooling, Big Air CPU coolers affix radiator fins to a heatsink base, usually by way of heat pipes. Some of our test have even shown these massive coolers outpacing a few of their liquid rivals. And while liquid systems usually have an edge in CPU temperature, a comparison of the cooling and noise shows these designs trading blows: Note that the Kraken X61 liquid cooler is roughly the same size as the NH-D15 Big Air cooler in the republished chart below.
The lack of a pump allows Big Air designs to be priced lower then liquid coolers, yet both have drawbacks, and these begin with size. First of all, a big air cooler is located directly over the CPU, which usually blocks access to memory slots and some cable connectors. Liquid coolers move the radiator to one of the case’s outer panels, leaving only the CPU socket covered by a water block or combination of water block and pump. On the other hand, “closed loop” coolers that have no fill port have been known to dry out over several years through microscopic leaks. Furthermore, Big Air coolers don’t have a pump to wear out or growl constantly. Modern pumps are usually very quiet, but they do make noise.
Perhaps the biggest reason to choose liquid over air isn’t the convenience of reaching RAM and cable connectors, but the fact that Big Air designs are usually large and heavy. These can weaken motherboards over a course of years, cause instant damage if the system is even slightly mishandled, or even bend down the CPU contacts of Intel’s Land Grid Array (LGA) design. We’ve even seen big-air coolers break off from their mounts and destroy the graphics cards in systems that were being shipped cross country.
In summary, liquid coolers are often better than air, but not always for reasons of CPU temperature. We generally use Big Air when a system is intended to remain stationary, and switch to liquid when the system is designed to be moved around or requires something much larger than the compact coolers we’ve consistently recommended to first and even second-time builders. Armed with enough information to make sense of our cooling reviews, we hope that you’ll stick around to engage in the discussion below.