Apple finally has heat dissipation!

At 1 a.m. on September 10, 2024, Apple held its online "Highlight Moment" event as scheduled, unveiling multiple new products across the Apple Watch, AirPods, and iPhone product lines. Among them, the highly anticipated iPhone 16 series boasts the following upgrades:

1. Camera control buttons (Lei Technology has published a dedicated review of the buttons, which can be searched and viewed across the internet);

2. A18 Pro (Lei Technology has also published a dedicated performance review, which can be searched and viewed across the internet);

3. Enhanced heat dissipation.

So, how does the heat dissipation (and performance) of the iPhone 16 series fare? Lei Technology promptly purchased the device (not a "media unit," ensuring an objective review without "considering Apple's feelings") and conducted a dedicated heat dissipation review. Before sharing our review conclusions, let's discuss the long-standing issue of iPhone's "inherited heating" problem.

Heat dissipation was once a weakness of the iPhone: overheating and impacting performance release

In the Android phone market, heat dissipation is a well-worn topic. Whether flagship or performance-oriented phones, manufacturers dedicate significant space to introducing their latest heat dissipation designs, claiming they significantly enhance gaming and daily use experiences.

The issue of phone overheating remains persistent, with every new generation of chips or even every new phone model eliciting questions like, "Does it get hot when gaming? Does it overheat during daily use?" Over time, a consensus has formed: heat dissipation is crucial.

Indeed, phone overheating not only affects handling but also indicates that the chip may throttle down due to excessive heat, preventing high temperatures from damaging other components. However, while Android phones have made heat dissipation a selling point, one major phone manufacturer has remained largely indifferent for years.

Image source: Xiaomi

Prior to the iPhone 16 series, Apple's heat dissipation was a significant issue. Although Apple employed screen heat dissipation films and increased thermal conductivity materials, the actual results were minimal. As chip performance increased, mere process technology upgrades could no longer address the power consumption issues arising from performance enhancements. Moreover, Apple's dual-layer motherboard design further hindered chip heat dissipation, leading to severe heat accumulation.

Especially after the release of the iPhone 15 series, users jokingly referred to it as the "Dragon Fruit" due to its proneness to overheating and subsequent performance throttling. While subsequent updates addressed the overheating issue by optimizing the throttling curve and reducing performance, it didn't fundamentally resolve the insufficient heat dissipation problem.

As the A18 series chips gained even more power and expanded the NPU area, Apple finally conceded: we need to address heat dissipation too!

Apple is finally tackling heat dissipation: How is it done?

Perhaps due to the iPhone 15 series' painful experience, rumors emerged before the iPhone 16 series launch that this generation would see heat dissipation upgrades, incorporating vapor chambers and other heat dissipation technologies already prevalent in Android phones.

During the event, Apple stated:

The iPhone 16 has improved its heat generation performance: Specifically, it positions the CPU in the center of the motherboard and enhances the phone's heat dissipation structure. According to Apple, this allows the iPhone 16 to sustain up to a 30% performance boost during gaming (take it with a grain of salt). The inclusion of the A18 chip also enables the iPhone 16 to run videos that were previously exclusive to the 15 Pro models, such as Ubisoft's upcoming Assassin's Creed Mirage.

The iPhone 16 Pro also enhances heat dissipation by improving its internal layout, with Apple claiming up to a 20% improvement. Additionally, it boasts improved battery life.

What's the real story?

After the official release of the iPhone 16 series, teardown videos revealed Apple's claimed "new-generation heat dissipation design."

In a nutshell, a newly designed metal shield covers the chip, transferring heat through a thermal pad into the metal frame, which then guides the heat outside. This design's advantage is that it significantly enhances heat dissipation efficiency without extensive internal structural modifications.

Image source: Bilibili

As seen in the teardown videos, the metal shield and thermal pad areas are not extensive. The only notable aspect, the metal vapor chamber, does not feature additional heat dissipation designs, unlike Android flagships that disperse heat and accelerate heat transfer through multiple heat dissipation materials and thermal modules.

For comparison, let's look at Xiaomi 14 Pro's heat dissipation design. Its metal vapor chamber extends to the motherboard position, directly connected through a thermal structure. It also incorporates separate heat dissipation designs for hardware like CMOS and inserts additional thermal modules wherever possible within the internal structure.

Image source: Bilibili

Even so, the Xiaomi 14 Pro still experiences overheating issues when playing games like Genshin Impact. While overheating isn't necessarily bad (it indicates heat isn't accumulating near the chip but being conducted to the body, enhancing the phone's experience under high power consumption for extended periods), it degrades handling comfort.

In other words, nearly all phones sacrifice handling comfort for performance experience since heat must dissipate somewhere, either through the frame or the back cover. Internal heat accumulation only worsens the situation.

So, the question arises: Is the iPhone 16's new heat dissipation design truly effective? And how does its heat-dissipating iPhone 16 perform in daily use?

How does its heat dissipation compare to Xiaomi 14? Games get hotter, but videos fare slightly better

In daily use, two primary scenarios lead to phone overheating: extended gaming and 4K video recording. Gaming overheating is particularly unacceptable as most performance-intensive mobile games require both hands, inevitably leading to one hand gripping the phone's upper half—often its hottest region.

Therefore, I first tested the phone's temperature during gaming. With an indoor temperature of 26°C, after 30 minutes of continuous Genshin Impact gameplay, the iPhone 16's maximum body temperature reached 43.2°C, while the Xiaomi 14 peaked at 37.2°C.

Image source: Lei Technology (left: iPhone 16, right: Xiaomi 14)

The temperature difference is evident, with the iPhone 16's upper half noticeably hot to the touch, while the Xiaomi 14 feels merely warm.

While 43.2°C isn't exceptionally high for a flagship phone, comparison highlights the iPhone 16's significantly higher temperature compared to the Xiaomi 14's 37.2°C.

Next, I conducted a prolonged 4K60fps recording test. After 30 minutes, the iPhone 16 peaked at 44.1°C, while the Xiaomi 14 reached 43.8°C. Both phones operated normally without overheating warnings, suggesting seamless recording until battery depletion.

Image source: Lei Technology (left: iPhone 16, right: Xiaomi 14)

However, air-conditioned room temperatures only represent part of our usage scenarios. What about high outdoor temperatures?

Image source: Lei Technology

At an outdoor temperature of 30°C, after 30 minutes of Genshin Impact, the iPhone 16 peaked at 44.5°C, with the lower-left corner reaching 39.4°C.

The top frame reached 41.5°C, and the bottom was 39.3°C.

For comparison, the Xiaomi 14 reached 38.5°C at this point.

Its side frames measured 38.1°C and 37.7°C.

Although the ambient temperature rose by 4°C, the phone's body temperature increase was minimal.

During subsequent 4K recording tests, results differed from indoor conditions. After 30 minutes, the iPhone 16 peaked at 44.6°C, while the Xiaomi reached 45.8°C, with the iPhone 16 slightly outperforming the Xiaomi 14.

Recording the frame temperatures revealed surprising results. The iPhone 16's frame temperature varied significantly, with the bottom at 36°C and the upper half at 43.1°C.

In contrast, the Xiaomi 14 showed a more uniform distribution, with the upper half at 43.1°C and the lower half at 44.4°C.

These findings highlight the differing heat dissipation designs. The iPhone 16 solely upgrades chip heat dissipation, leaving the CMOS module unchanged. Thus, CMOS heat accumulates in the upper half.

Xiaomi 14's teardown reveals a dedicated heat dissipation structure for the CMOS connected to the vapor chamber, evenly distributing heat across the phone's body.

However, Xiaomi 14's CMOS overheating is more pronounced, with its body temperature still higher than the iPhone 16, despite a more efficient heat dissipation system.

Yet, the iPhone 16's marginal victory in 4K recording fails to explain why it runs hotter during gaming. While the iPhone 16's nearly flawless framerate curve and near-60fps average are impressive, 43.2°C is undeniably high.

Think the heat dissipation test ends here? Not quite. There's another overlooked aspect: how long does it take for the phone to cool down after use? The iPhone 16 answers in three minutes.

Three minutes after the test, the iPhone 16's maximum temperature dropped to 35.9°C, with side temperatures at 34.9°C.

In comparison, the Xiaomi 14's maximum temperature was 42.2°C, with side temperatures at 39.9°C.

These figures suggest the iPhone 16's heat exchange efficiency is impressive, even surpassing the similarly sized Xiaomi 14 with an aluminum alloy frame. Its internal heat accumulation is minimal, allowing swift heat dissipation.

Finally, let's talk about the conclusion. Throughout the entire testing process, neither the iPhone 16 nor the Xiaomi 14 experienced issues like lag or overheating warnings, and the iPhone 16's performance has indeed improved significantly compared to its predecessors.

Since the A18 chip in the iPhone 16 performs almost identically to the A17 Pro in the iPhone 15 Pro, and most likely, you haven't forgotten the nickname 'Dragon Fruit' given to the iPhone 15 Pro. During previous tests, the maximum temperature on the back cover exceeded 50°C (at room temperature of 26°C), whereas under the same performance conditions, the iPhone 16 only reached a maximum temperature of around 45°C even in an outdoor environment of 30°C.

In other words, during daily use, as long as you're not recording 4K60fps video for extended periods or playing intensive 3D games, overheating issues should be minimal, even under direct sunlight. In indoor environments, you shouldn't encounter situations similar to the iPhone 15 Pro's transformation into a 'Dragon' due to overheating.

Source: Leikeji