Asus AeroActive Cooler 6 vs Kunai 3: Which should you buy?

The Asus ROG Phone 6 is the best smartphone made specifically for gaming you can get, but if you’re really keen to make the most of it — and make games even more satisfying to play — then Asus has a pair of accessories to tempt you. The new Asus AeroActive Cooler 6 joins an updated version of the Kunai 3 gamepad, and both perform quite different tasks. Are either worth getting?

What are these ROG Phone 6 accessories?

The AeroCooler Active 6 is an external fan for the ROG Phone 6 and ROG Phone 6 Pro, but unlike some previous versions, it also has four physical buttons on the case — ready to be mapped to controls in a game. Additionally, it has a kickstand to hold the phone upright, plus an RGB light array inside. It attaches to the ROG Phone 6 through the side-mounted USB Type-C port, and there’s a pass-through port so it can still be used to charge or power the phone. It’s worth noting the latest cooler is only for the ROG Phone 6, and previous AeroCooler accessories won’t work with it.

The Asus ROG Phone 6 Pro with the Kunai 3 controller and AeroActive Cooler 6 fan.
Andy Boxall/Digital Trends

There are three cooling modes. Basic cooling takes place using the fan only, Frosty mode increases the intensity and takes power from the phone, while the top Frozen mode requires the AeroActive Cooler 6 to be plugged into a power source. Asus says it has the ability to reduce surface temperatures by up to 25 degrees centigrade and is best suited to people who play intensive games for more than an hour at a time.

The Kunai 3 gamepad released with the ROG Phone 6 is the same as the Kunai 3 controller released with the ROG Phone 5, but this time it’s available in a new Moonlight White color. The modular controller system is reminiscent of Nintendo’s Joy-Con controller for the Switch. It’s made up of two controller parts, a central charging section, a separate grip, and a skeleton frame made for the ROG Phone 6. It connects to the phone with Bluetooth when used on its own, or via USB when the controllers are connected to either side of the skeleton frame.

The Asus ROG Phone 6 Pro with the Kunai 3 controller and AeroActive Cooler 6 fan.
Andy Boxall/Digital Trends

There are 10 mappable buttons and analog triggers spread over the front and back of the controllers, two joysticks, and various menu buttons on the Kunai 3. There’s even an RGB strip light on the left controller. It comes with a small carry case that’s suitable for “Mobility Mode,” where you forgo using the grip section on the wireless controller.

AeroActive Cooler 6

Fitting the AeroActive Cooler 6 to the ROG Phone 6 is easy. You pop the top of the fan by pressing a button, slot it into the side-mounted USB Type-C port, and push the top section back down to lock it all in place. It should start automatically, and its options are presented under the notification shade. Here, you can turn it on or off, change the RGB lighting mode, and select the level of cooling required. However, the AeroActive Cooler 6 is intelligent and monitors the device’s temperature, ready to adjust the amount of cooling required.

Asus ROG Phone 6 Pro with the AeroActive Cooler 6 attached.
Andy Boxall/Digital Trends

It’s quite a beast on the back of the ROG Phone 6, increasing the weight of the already heavy phone to 360 grams, all of which is slung out over the back. It upsets the balance of the phone, but worse is that the physical buttons aren’t all that reachable. It makes them not very comfortable to press because they’re set very close to the center of the phone and then extended out by a couple of centimeters. Unless you have quite large hands, the buttons will be awkward. I far preferred using the ROG Phone 6’s shoulder buttons when additional buttons were required in a game.

In Smart mode, the fan does generate some noise, but it’s easily ignored. Plug in the ROG Phone 6’s charger to activate the lowest Frozen setting, and along with the speed and cooling increase comes a lot more noise. It’s not deafening, but it’s considerably more noticeable.

If the buttons aren’t really a selling point, the cooling had better really do its job well. To find out, I ran 3DMark’s Wild Life Extreme Stress Test, which puts the phone through its paces for 20 minutes. First, I tried this on a naked ROG Phone 6 Pro with X Mode active, then ran the same test with the AeroActive Cooler 6 fitted. The test is ideal because the app provides device temperature data at the end.

Without the additional fan, the ROG Phone 6 Pro got very hot, and when it had completed the test, the temperature range had jumped from 33 degrees centigrade to 52 degrees centigrade. Furthermore, it reduced the battery from 57% to 43% during the test. After turning the phone off and letting it cool down, the test was repeated, this time with the AeroActive Cooler 6 attached in Smart mode and connected to the charger in case it required the power-intensive Frozen mode.

The temperature range went from 32 degrees to 48 degrees, and the lower maximum made a considerable difference to the battery consumption, which fell from 42% to 39%. Looking at the stress test itself — which consists of four repeated sections — the best score without the cooler was 2773, and the lowest was 2543. With the AeroActive Cooler attached, the phone recorded a top score of 2818 and a lowest of 2571.

There’s an obvious performance difference with the AeroActive Cooler 6 fitted, but it’s not huge, and it was only really evident when the phone was under a very high level of load. The AeroActive Cooler 6 is for those people who will play extremely power-intensive games for long periods of time when it will assist with more performance and lower battery drain. If you only play simple games for less than 30 minutes, you probably won’t get much benefit from the AeroActive Cooler 6.

Kunai 3 Gamepad

If the button placement on the AeroActive Cooler 6 is awkward, the button placement on the Kunai 3 gamepad is just about perfect, and its design clearly comes from a team that understands gaming and associated ergonomics. Not only that, because there are three different ways to use the Kunai 3, its versatility makes it suitable for more people. If you don’t find touchscreens responsive or natural enough for serious gaming, this is the gadget for you.

The ROG Phone 6 Pro with the Kunai 3 controller, playing Diablo Immortal.
Andy Boxall/Digital Trends

Using the Kunai 3 in handheld mode, where the controllers are attached to the skeleton frame, is my personal preference. On paper, it’s quite heavy at 376 grams, but because most of that weight is the phone in the middle, the balance is excellent. You’re free to hold it comfortably and still use all the many buttons and the two joysticks. I find the sticks to be just the right height and to have the right amount of movement, too. Mapping the buttons is simple — a swipe in the top left of the screen to show the Game Genie option list — and it’s easy to save your settings for future use.

The buttons don’t have a huge amount of feel, though, and the rear-mounted and shoulder buttons are clicky and not especially tactile. They are definitely not as pleasing to use as a gaming console controller or the Nintendo Switch Lite. Overall portability is also a problem. The skeleton frame doesn’t really double as a case, so you won’t want to keep it on your phone. And if you want to use the grip when the controllers are in wireless mode, it doesn’t fit in the supplied case. The case is just for the wireless controllers, the charging dock, and a USB cable.

In wireless mode, the controller feels quite small when you don’t hold it with the separate grip, but with it attached, the controller is very well sized and still very light at 198 grams. Connecting with Bluetooth is a little fiddly as you have to hold down the Home button on the controller for a set period of time, but do it for too long, and the controller switches off. I have played Diablo Immortal several times using the wireless controller and have not found latency to be an issue.

The Kunai 3 controller makes games more fun. It’s the accessory to buy if you’re into games, but not into gaming to the point where the AeroActive Cooler 6 makes sense, in that you play quite a lot but not competitively. It fits the ROG Phone 6 perfectly, it’s well made, and feels pretty sturdy, too. Do consider the type of games you play before buying it, though, as it’s best suited to games with multiple touchscreen controls and a requirement to use an onscreen virtual joystick. You won’t get much benefit if you mostly play simpler games.

Which one to buy?

The Kunai 3 adds another dimension to the ROG Phone 6, turning it into a more usable, more ergonomic, and more fun gaming device. The AeroCooler Active 6 improves the ROG Phone 6’s performance when playing graphically intensive games for long periods of time in one go. They do pair up nicely if you only intend to use the Kunai 3’s wireless mode, when the AeroCooler Active 6’s kickstand comes in very handy to keep the phone upright in front of you. But the two can’t be used together when the skeleton case is attached to the phone.

There’s also a difference in price. The AeroActive Cooler 6 costs 79 British pounds or 90 euros, while the Kunai 3 is 106 pounds or 120 euros. Prices for the U.S. launch have not been announced yet, but these prices convert over to about $95 for the fan and about $126 for the controller.

Ultimately, the Kunai 3 has far wider appeal, and more people will get enjoyment from it. Comparatively, the AeroActive Cooler 6 is far more niche and aimed at hardcore mobile gamers, but if you think you need an additional fan, there’s nothing else quite like it.

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