The latest iPhone 15 models have recently been released in stores, but there are already reports of overheating issues. Users and members of the Android Authority team have reported high temperatures particularly with the more advanced iPhone 15 Pro and Pro Max models, suggesting that the new and powerful Apple A17 Pro processor could be a contributing factor. There have also been reports of the phones getting hot while being charged, which is surprising considering their relatively low 20W charging power through USB-C.
I brought the iPhone 15 Pro (purchased for testing and review) to the laboratory to investigate the situation.
The A17 Pro chip from Apple is causing issues.
To confirm the presence of any problems, we used a temperature measurement device to track the highest temperatures on the back of the phone during different tasks. We also conducted identical tests on the Google Pixel 7 Pro and Samsung Galaxy S23 Ultra without cases, background tasks, and with a cooling period between each run. Now, let’s move on to the findings.
Firstly, when performing everyday tasks like streaming videos and scrolling through the web, the iPhone 15 has a slightly higher temperature compared to the S23 Ultra and Pixel 7 Pro. However, the difference is not significant enough to cause any issues with the phone. The temperature stays below 30°C, which is cool enough to not be noticeable.
When using Geekbench 6 to test the CPUs, the results show that Apple’s phone is slightly warmer than its competitors, but still falls within a similar range. While the iPhone 15 Pro may feel warm to the touch when completing intensive tasks, it is not overly uncomfortable and only slightly warmer than the two other devices we compared it to. On average, the iPhone 15 Pro was 2.5% to 5% hotter in these tests, which may or may not be noticeable depending on the user’s activity.
However, when using more complex features that involve multiple SoC components, it becomes evident that the A17 Pro chip has some issues. Turning on the six-core GPU leads to a rapid increase in temperature. In just five minutes of running the 3DMark Wild Life stress test, our iPhone 15 Pro surpasses 40°C. By the end of the 20-minute test, the phone reaches a peak of 47°C, which is almost too hot to hold. While the Galaxy S23 Ultra also struggles in this scenario, the iPhone 15 Pro runs 5.7% hotter, which is concerning for any handheld device. Approaching 50°C with any workload is cause for concern.
In more challenging situations, the temperature of the iPhone 15 Pro can rise above 40°C, causing discomfort when held.
Our 4K/60 video recording test showcases the most significant discrepancy. After just five minutes, the iPhone 15 Pro is about 7°C hotter than the S23 Ultra and 4°C hotter than the Pixel 7 Pro, a phone already widely regarded as too warm. Worse, the iPhone 15 Pro far exceeds an acceptable level of comfort in the hand after extending the test to 10 minutes.
After reviewing the data, it is evident that the iPhone 15 Pro consistently has higher temperature readings compared to the Galaxy S23 Ultra and Pixel 7 Pro in all of our experiments. While the difference may be minimal at times, it is clear that the more demanding tasks on Apple’s latest chip reveal a noticeable disparity. This supports the claims that the iPhone 15 Pro and Pro Max have a tendency to overheat.
The charging of iPhone 15 using USB-C also generates excessive heat.
Aamir Siddiqui from Android Authority reports:
While the iPhone 15 Pro appears to be popular, are there any concerns regarding charging?
Unfortunately, iOS does not provide a method for accurately measuring the internal battery levels. Therefore, we have opted to measure the highest external case temperature instead. It is important to note that the actual working temperature of the battery may be 2°C to 4°C higher than our recorded external readings, depending on the effectiveness of Apple’s cooling system. In order to test the charging abilities of the iPhone 15 Pro, we utilized a 30W Apple USB-C charger and the USB-C to USB-C cable that came with the device.
The highest recorded temperature was 36.1°C, although the Pro Max reached an even higher 40.2°C. This aligns with the phone exceeding the 20W limit stated in Apple’s documentation. It has been speculated that these phones charge at a faster rate than what is officially stated by Apple, and this appears to be true, although a limit is enforced to prevent temperatures from getting too high. If the Pro Max consumes more power than the Pro, this could explain the reports of even higher temperatures from other sources.
During our test, we refrained from using the phone, however, we noted that the temperature rose above 40°C when browsing the web and watching videos while the iPhone 15 Pro was charging. Holding the phone while completing tasks during charging can become uncomfortable. To address this issue, Apple limits the charging speed when the phone becomes too hot. In some cases, it may even decrease to 5W, which takes a longer time to fully charge the phone.
Although the power levels may be low, the iPhone 15 Pro and Pro Max charge at similar or higher temperatures compared to other competitors.
When comparing the outside temperature of the iPhone 15 Pro to the inside battery recording of the Samsung Galaxy S23 Ultra, it is clear that there is a significant difference. It is important to note that Apple’s charging power maxes out at 20W, while the S23 Ultra can handle up to 45W. The highest internal temperature reached by Samsung was 35.5°C, which is lower than Apple’s estimated range of 38-40°C (a range where other manufacturers typically limit temperatures), based on the outside temperature reading. Additionally, our iPhone 15 Pro heated up much quicker, indicating potential issues with heat dissipation.
Although the temperatures we recorded are not as concerning as the ones seen when putting pressure on the A17 Pro chip, they are still quite high considering the relatively lower power and slow charging speeds of the iPhone 15 Pro. It takes a frustrating 90 minutes to fully charge the phone.
Can the iPhone 15 become too hot?
It is undeniable that the iPhone 15 Pro that we have tested runs hot, perhaps too hot. Even though the phone’s A17 Pro chipset has a supposed advantage in manufacturing compared to the competitors we tested, with a more efficient 3nm TSMC node compared to the Snapdragon 8 Gen 2’s 4nm node in the Galaxy S23 Ultra and the Pixel 7 Pro’s Tensor G2’s 5nm Samsung node, it seems that Apple has utilized this advantage to prioritize performance, such as adding an additional GPU core, which leads to higher temperatures when the chip is under pressure.
Similarly, the charging performance of the phone is underwhelming when compared to other Android devices with fast-charging capabilities. Not only are the charging speeds slow, but the phone also becomes noticeably warm to the touch during charging. This could potentially lead to higher internal temperatures, which is concerning for the overall battery lifespan. It seems that the iPhone 15 Pro Max fares even worse in this aspect, as it experiences greater power surges resulting in even higher temperatures.
The Pro and Pro Max models from Apple are prone to heating problems, particularly among their target consumers.
The final outcome is two phones that may not always be overheating, but can be heated to higher temperatures by the users Apple aims for. Those who play games, do multiple tasks, and make videos are most likely to use the iPhone 15 Pro and Pro Max in a way that causes them to reach temperatures that are too hot to hold. If you were planning on buying the newest iPhone, it might be wise to wait and see if Apple can fix this problem in a future software update. If you already have one, it would be a good idea to remove the case while charging and allow the phone to cool down after using demanding apps.