At idle, liquid coolers can often be at a disadvantage, as their pumps must keep running, despite the low load. Let's see how our contenders fare versus our monster air cooler from Noctua:
Very interesting. While the Noctua is indeed among the quietest coolers in the race, the Reeven Naia 240 came up with a shocking win, registering as nearly inaudible in our idle testing. But both of these coolers actually had a weakness not reflected in the numbers. The Noctua emitted some resonance, which we attribute to the dual-fan arrangement, causing airflows of different velocities to intersect each others' path. We've never been sold on dual-fan air coolers, and this is one of the drawbacks. It's not perceived as something loud, but rather a disruption in frequency, and human ears are very good at picking that kind of thing up. Similarly, the Reeven had a slight gurgling sound every few seconds, which may have resulted from running a low pump speed at idle.
Of note, the Thermaltake Water 3.0 wouldn't work properly at all with the default fan curve (which set fans and pumps at 27% when below 40°C). It made a tremendous amount of noise, as the slow pump clearly wasn't able to pull liquid through properly. We had to manually adjust the motherboard controls for the Thermaltake to ensure that pump RPMs stayed above 1000RPM; the 27% speed we used for other coolers set it at 900RPM. We make special note of this in case others come across the problem and think their Thermaltake coolers are broken - they are not! Alas, this did end up pushing the Thermaltake up to pretty high noise levels, so if quiet idles are your goal, this is not the cooler for you. We know a lot of older liquid coolers got around this problem with a fixed pump speed that was always running at maximum, but the drawback to this, as we'll discuss more on the next page, is terrible idle noise. We'd much rather have to tinker with our idle fan curves to dial in a good setting for a liquid cooler's pump than contend with an always-maxed arrangement.
While we really don't care about temperatures at idle all that much, we would note that our air cooler was the hottest, and our most expensive liquid cooler, the 280mm Thermaltake, was the coolest, by far.
This is the test that most closely approximates the load presented by typical high-intensity applications, pushing our system to a 175W power draw at the wall. We've found these results to be nearly identical to what you'd see in a multi-player match of the game Battlefield 1, which is about as intense as a game can get. And if this is your typical "max load," well then we have some clear winners and some clear losers, and they are often one and the same! The massive radiator and four-fan array on the Arctic Liquid Freezer 240 propels it to a big win, even beating out Thermaltake's 280mm model, but ouch, look at those noise levels. Terrible, just terrible! On the flipside, the Reeven Naia was excellent and the Thermaltake was simply sublime, with the second best temperature and the lowest noise level. Our Noctua air cooler proved that massive amounts of metal can nearly take the place of liquid coolant, running a lot quieter than the CoolerMaster while providing nearly the same performance.
Now we really turn up the heat. Prime95 Small FFTs is an insane load, and our eight-core test system was drawing 200W during this test. Our reference Noctua air cooler again holds its own, nearly matching the MasterLiquid 240 while remaining much quieter. A very good showing for big air here, and not bad for the budget MasterLiquid, which needs to turn its fans at a higher RPM to compensate for what is probably a more basic radiator design. CoolerMaster lost a big lawsuit a few years ago to Asetek, and has since embarked upon designing its own coolers from scratch. If this is the result, we think it's not bad at all, and the lower price can probably be traced directly back to the fact that Asetek isn't getting a cut.
Alas, if you want the best performance, you need high-end liquid, and we were simply shocked at how well the Reeven Naia and Thermaltake Water 3.0 did despite noise levels that were below the Noctua's! If you want to have your cake and eat it too, the combination of high performance and low noise levels these two coolers offer at their respective pricepoints is impressive.
And finally, we come again to the Arctic Freezer Liquid 240, which is clearly the "muscle car" of this roundup. It's all about displacement, baby, and the Arctic comes away with a win here, but abandons all semblance of finesse in the process. Of particular note, the pump in our Arctic sample was registering at 4115RPM in this test, which seems absurdly fast, but it would certainly go a long way to explaining why the thing is so incredibly loud. The fans actually aren't turning that fast, so we tend to trust the pump RPM reading we saw in HWMonitor. We find this particularly ironic given that Arctic is headquartered in Switzerland, the home of some of the most finely-tuned wrist-mounted machines in the world (i.e., watches). As we mentioned earlier, the Arctic is just a pumped-up Asetek clone, so in reality, it isn't of Swiss provenance at all... it's Danish!