Early PCs seldom had more than a tiny, weak fan on the back of the case to push out excess heat generated by the internal electronics. As transistors shrank and chips grew faster and more complex, CPUs began running hotter and reaching dangerous temperatures - so hot, in fact, that the little case fan couldn’t protect the delicate electronics from burning out.
To address this, PC manufacturers began adding fans dedicated to cooling this nerve center of the motherboard. Today, with high end gaming machines consuming up to 1000W or more, enormous heat is generated not just by the CPU, but by the memory, north and south bridges, and the graphics card. To expel this heat from inside the case, larger and faster case fans are needed to keep everything running at a safe, relatively cool temperature.
For the past few years, PC accessory vendors have been marketing liquid cooling systems. These products promise to cool more efficiently, and more quietly, than traditional fans - at the same time adding several hundred dollars to the total price tag of a new machine. The question is: is this just a pricey gimmick, or is this the next logical step in the progression of ever more powerful machines?
What is liquid cooling?
Liquid cooling your computer involves two separate components connected together by plastic PVC tubing filled with coolant.
The first component is the pump and radiator. The pump is responsible for circulating coolant throughout your computer to absorb the heat generated by the various components. The coolant is then pumped through a radiator, located outside of the case, which dissipates the heat outside.
The second component is the cooling blocks. Cooling blocks are attached to one or more of your motherboard components. The metal cooling blocks draw heat away from critical components on your motherboard, and coolant flowing through the blocks carries the heat to the radiator.
Fan cooling of components generally means drawing heat away from the electronics and filling the inside of the case with hot air – external case fans ultimately remove the heat from the case. Liquid cooling immediately takes the heat out of the case. Also, liquid coolant holds 4 times more heat than air, and transfers heat 30 times faster.
When should you liquid cool?
Simply put: most people do not need liquid cooling. Desktop computers built to suit typical business applications - browsing, email, productivity applications, etc. - can easily get by on lower-end systems with minimal cooling requirements. Even many gaming machines are well served by low to mid-range computers.
Higher end machines with top-of-the-line CPUs, however, are massive heat generators – and most CPU fans built for Intel’s latest line of Core i7 processors are monstrous and louder than a NASCAR pit lane. Added to the din of the other fans and components in the computer, these high RPM fans can be very distracting. Liquid cooling the CPU can dramatically quiet the overall noise level coming from the box.
If you’re an overclocker, liquid cooling the CPU might be a necessity as there might not be any fan capable of keeping everything at a safe temperature. You may also want to buy cooling blocks for your north bridge.
When should you not liquid cool?
If you have a low-end PC, noise and high temperatures are unlikely to be a problem. You can save hundreds of dollars sticking to traditional fan cooling.
If you have a small case, you probably don’t have enough room to fit all of the cooling blocks and hoses necessary to install the cooling system. For lqiuid cooling, plan on buying a full tower case in order to have plenty of room to work with. A mid-tower case might work for simpler configurations, but it’d be a tight fit.
Finally, don’t liquid cool if you’re on a tight budget. If you’re not overclocking, you can always buy traditional fans to keep your motherboard safely cool. You may want to put some distance or baffling between you and your machine to minimize the noise, but you won’t have to worry about burning up your machine.
What should you liquid cool?
If you liquid cool nothing else, at least put a cooling block on the CPU. In fact, it’s not unreasonable to have a system where only the CPU is liquid cooled. This is the primary heat generating component inside your case. Not only will the CPU quietly be kept to a safe temperature, the heat will be carried outside the case by the tubing – this reduces the load on the external case fans carry heat out from the inside.
Memory isn’t necessarily at risk of overheating (unless you’re overclocking), so it may not need special attention. However, if you’ve filled up all of the DIMM slots, you might be pushing your luck. The instructions to the ASUS P6T motherboard actually recommend adding additional RAM cooling when all six slots are used.
Think hard before liquid cooling memory. Because the distance between DIMM slots is variable, RAM liquid coolers often involve sliding connectors. These connectors are prone to leakage, and even the tiniest leak of electrically conductive coolant can ruin parts of your system. If your memory is getting too hot, consider a traditional fan cooler dedicated to RAM.
High-end graphics cards might benefit from liquid cooling simply to reduce noise levels, but even that’s a stretch. Many of the highest performing graphics cards on the market today still have reasonably quiet fans. Also, liquid cooling these graphics cards means removing the fan over the GPU, thus invalidating your warranty.
The north bridge and south bridge sometimes need additional cooling in overclocking situations.
Finally, don’t bother cooling your hard drive or power supply. Neither component is a substantial heat source. In fact, hooking up too many cooling blocks in your loop will cause your pump to work harder and ultimately reduce the efficiency of your setup. If you really feel you need to liquid cool every component in your box, consider adding a second loop.
How to test
Once you have your liquid cooling all set up, how do you load up your system to test its effectiveness? For starters, I recommend installing a cooling system with temperature monitors. You want to make sure your motherboard temperatures don’t enter a dangerous range while load testing your system.
To create a load, install BOINC. BOINC describes itself as using “the idle time on your computer to cure diseases, study global warming, discover pulsars, and do many other types of scientific research”. Depending on the BOINC project you subscribe to, your computer will be assigned a small portion of a massive, mathematically intensive research problem. By default, the computation will consume all available CPU cycles on your computer, and a goodly portion of your memory.
Keep a close eye on your system temperatures when you start this test. I ran a BOINC test on my ASUS P6T motherboard with a Core i7 processor and 12G of GSkill RAM. I was liquid cooling the CPU, but not memory. In under 30 seconds, the CPU was running a cool 30C, but RAM was setting off the temperature alarm mat 55C!
Initially, my RAM had no dedicated cooling. I removed the liquid cooling blocks because I couldn’t stop the leaking. Based on this test, I added a dedicated, low-noise RAM cooler and now my box behaves beautifully.
If you choose to liquid cool, my best advice is “be patient”. Getting it right requires some experimentation.
Finally, select a brightly colored coolant like pink, bright blue, or fluorescent green. This isn’t just about looking cool – these eye catching colors make spotting leaks on your motherboard a lot easier than a dull, colorless coolant.
My final thought? Be cool, man, be cool.