Testing the Cooling Efficiency of OnePlus Nord 4’s Metal Back

Other than a few deviations, OnePlus has a penchant for value products. The premium OnePlus 12 offers a (mostly) superior set of features and a refined experience over similarly-priced flagships such as the Galaxy S24 Plus or the Pixel 8 Pro. Similarly, the $500 OnePlus 12R offers exceptional performance and a flagship-like experience for its price. The OnePlus Nord 4, which sits in a price bracket right under the 12R, has its own benefits, but one that stands out is its metal back.

The OnePlus Nord 4 is the first and currently the only 5G phone to feature a metal back panel. Not only is it a striking design, but it also has another trait that perceivably makes it more exciting than other phones: Its metal body potentially helps improve performance.

Metal is a better conductor of heat than glass or plastic and is superior at radiating heat outward — meaning the Nord 4 should run cooler than other phones. The effectiveness at cooling is also expected to complement the chipset driving the Nord 4 (the Snapdragon 7 Plus Gen 3). Despite being a victim of Qualcomm’s confusing naming, the Snapdragon 7 Plus Gen 3 is potent enough to run most demanding tasks and is likely geared to run AI applications in the future.

So, does the Nord 4’s metal back help its Snapdragon chip run better and cooler? I found out.

How I tested Nord 4’s cooling

The biggest perceived benefit of the metal back when it comes to gaming. In addition to the vapor cooling chamber inside the phone, the metal back helps radiate inner heat generated from the chipset or the battery — the two primary sources of heat inside the phone. I played around (literally) with the OnePlus Nord 4 extensively to see if the theory holds up in practice.

To evaluate the metal back’s effects on the Nord 4’s performance, I set out to test how effectively it prevents heat buildup inside the body. The evaluation was divided into three parts, or potential contributors of heat generation and trapping inside the phone. Other than gaming, I also tested challenging scenarios, such as 4K video recording and high-speed charging, that can lead to the phone getting hot.

For each of these tests, I ran the tasks for 30 minutes to let the heat build up inside the body and on the surface. After the completion of each task, I waited for the phone to cool down to the original temperatures using an infrared thermal camera and noted the time taken in each case. Here’s how the tests panned out.

Heating while 4K video recording

Video recording constantly engages multiple parts, which, besides the camera itself, include the phone’s chipset, storage, and image signal processor (ISP). The display being constantly engaged is yet another reason for the hardware to feel burdened — and, therefore, heat up as a result. So, for my analysis, I set the OnePlus Nord 4 to record a 4K video at 60 frames per second.

The video was shot in an air-conditioned room, despite which the phone’s external surface heated up significantly. After I ended the recording, I left the phone to cool down. Here are my primary findings:

• Ambient temperature: 82 degrees Fahrenheit
• Starting temperature (before video recording): 88 degrees F
• Temperature after 30 minutes: 102 degrees F
• Time taken to return to original temperature: 17 minutes

While the 17-minute span may seem harrowing, the warmth subsided within five minutes, and the phone started to feel cold.

How cool is fast charging?

The Nord 4 charges at 100W, which is commendably fast. Although the phone charges fully within 35 to 40 minutes, that warrants some heat generation in the process. I followed a similar process as the last time but with one key change. The phone was charged and subsequently left to cool down without any air conditioning. Here is what I found out:

• Ambient temperature: 91 degrees Fahrenheit
• Starting temperature: 95 degrees F
• Temperature after 30 minutes: 104 degrees F
• Time taken to return to original temperature: 28 minutes

It took longer to return to its original temperature (which still seemed dangerous due to the warm room). However, the warm room did not significantly slow down charging as I thought it would.

The Nord 4’s ultimate test — gaming

Gaming is easily one of the most demanding tasks for a phone. Additionally, its propensity to heat is bound to increase if the hardware struggles to keep up with the demands of the game — and that is what makes the Nord 4, a non-flagship phone, the ideal candidate to study the effects of heating.

For this series of tests, I ran one of the graphically heaviest cross-platform games, Genshin Impact, at the Highest graphics settings with textures set to High and the intended frame rate set to 60 fps. These settings make the best of hardware sweat, so testing how the Nord 4 holds up would have given us the insights we were looking for.

Additionally, I recorded the Nord 4’s performance using GameBench, a professional game-benchmarking tool. The following summarizes the findings from running the same instance of Genshin Impact on the three phones:

The results show a convincing picture of the Nord 4’s ability to dissipate heat better than the other two devices. The Realme GT 6, with a plastic back, retains the most heat internally and takes the longest to return to its original temperature. The OnePlus 12R understandably generated less heat internally but traps a significant amount of heat inside the body.

Overall, the OnePlus Nord 4 with its metal back showcases effective cooling, especially during demanding tasks like gaming. While there are drawbacks to metal constructions, the benefits in terms of performance and heat dissipation are clear.