We ran the tests: Foldable phones still have an overheating problem

The Motorola Razr Ultra (2026) has a lot to offer, with a good-sized 5,000mAh silicon-carbon battery, speedy charging, and cover-screen software that’s arguably the best in the business. However, the phone is rather pricey at $1,500, especially when you consider that it runs a last-gen processor, yet still flat-out overheated and force-closed our usual suite of benchmark stress tests.

While the phone didn’t heat up noticeably during day-to-day tasks and even some more demanding workloads, this is just another example showing that, when pushing maximum performance for any serious length of time, modern smartphones buckle over — particularly foldables. I can’t help but wonder if temperatures, rather than just cost, are at least part of the reason not to jump to this year’s Snapdragon 8 Elite Gen 5, though it’s still bizarre that last year’s Razr Ultra model powered through the stress tests just fine.

It wouldn’t be surprising, given that we’ve seen the 8 Elite Gen 5 hit up to 49.5°C in some flagship smartphones we’ve tested. Crammed into a restrictive, foldable form factor, extreme performance can lead to even higher temperatures. Increasingly, if you want to sustain peak flagship performance for any length of time, you need a large battery and a robust cooling solution.

For foldables, it doesn’t seem to matter whether you’re rocking current- or last-gen silicon; temperatures under stress can be a concern.

The benchmark numbers don’t lie

Just take a look at the tests from recent foldables that actually completed the increasingly modest 3DMark Wild Life stress tests. Samsung foldables and last year’s Razr Ultra all hover around 40°C (104°F) well before the end of the test. The exception to the rule is Motorola’s own Razr Fold, which tops out at a far more comfortable 35°C (95°F) and throttles back performance more gradually than rivals.

Let’s take a closer look at the Razr Fold, which eschewed Elite-tier silicon for the slightly more economical, but by no means budget, Qualcomm Snapdragon 8 Gen 5. While not quite as compact as the clamshell Razr or Samsung’s Flip, testing shows it runs cooler and delivers higher sustained performance than the Z Fold 7, and by extension, flipable foldables as well. It’s not hard to imagine this chip would have helped the Ultra keep cool enough to complete our stress test while providing very comparable performance to last-gen.

I feel like a broken record, but phones don’t need to ship with the very fastest chip possible to offer robust everyday and even gaming performance. Chips like the 8 Gen 5 won’t struggle to hit 60fps or higher in most Android games and emulators, even though it’s not quite a benchmark topper. In fact, sometimes it’s better not to pick the fastest (and hottest) chips on the market and instead settle for something that’s easier on battery draw and thermal performance, especially in this form factor.

The fastest chip isn’t always the right choice

While the Razr Ultra raises eyebrows for failing our stress tests with last year’s silicon, I’m equally concerned that the upcoming Samsung Galaxy Z Flip 8 will have a Snapdragon 8 Elite Gen 5 chip in the US — possibly even the slightly higher-clocked “for Galaxy” variant. Based on historical data, it’s highly unlikely that the Flip will be able to sustain the Elite chip’s peak performance for long. While it might not overheat or close down apps as heat builds, quick thermal throttling is likely and could even leave the handset rather warm if you decide to break out some games.

Unfortunately, it looks like Samsung’s Exynos 2600 chip isn’t exactly a cool customer in the Galaxy S26 and S26 Plus either. The chip has proven a tad warmer than Snapdragon alternatives we’ve tested and seems to warm up faster. Samsung may be opting for the marginally cooler of the two options by putting Snapdragon in the next Flip in some markets, though neither chip will unlock its full potential when crammed into the extra-compact form factor of a clamshell foldable.

Now you might argue that few clamshell customers are buying devices like the Razr Plus and Z Flip for extreme-performance use cases, so why worry about the heat from an extreme stress test? A fair point, but this only further raises the question of why cram expensive, top-of-the-range silicon into them in the first place? Keeping up premium appearances matters to an extent, but customers would be equally happy if a more frugal chip meant their batteries lasted longer instead — especially when foldable phone batteries are often smaller to begin with.

While bendy booklets are built for multitasking, clamshells are, by definition, more conservative. We already happily trade battery size and cutting-edge camera hardware for a more pocket-friendly form factor. Brands would do well to consider the heat in our palms and how often we’ll reach for a cable when pairing their latest fashionable foldable innovations with the latest and greatest processors.