Foldable smartphones (like the recent iPhone Duo) have gained a lot of traction worldwide, but they are especially well-liked in Asia (particularly in China, where they appear to be very popular). There are obvious pros and cons when choosing a device like that, and a recent piece of information was shared that can help buyers make more informed decisions.

It looks like the foldables can indeed deliver faster mobile data speeds than traditional slab-style phones, but new Ookla Speedtest data indicates that higher performance can come with increased heat generation.

The findings compare foldable and conventional smartphones using devices with similar underlying processors. Models such as the Galaxy Z Fold 8 and Galaxy S26 Ultra were evaluated to examine differences in everyday network performance. In general, the foldable models recorded higher download and upload speeds on mobile networks. 

However, the improved connectivity performance was accompanied by higher temperatures in some devices. The Galaxy Z Flip 6 recorded the highest temperatures among the tested models. The Galaxy Z Fold 8 and Z Fold 8 Ultra also reached higher battery temperatures than their predecessors. 

According to the report, the changes may be related to the thinner designs of newer foldable phones and the removal of internal cooling chambers. Manufacturers face additional engineering challenges when trying to maintain thermal control while reducing the thickness of flexible devices. 

The testing also found some differences in signal quality. Foldable smartphones generally performed slightly worse than conventional models under normal signal conditions. The Galaxy Z Flip 6, for example, recorded the weakest signal performance in standard conditions. However, it performed better than the corresponding standard model when network conditions became unstable. The differences were relatively small and may have limited practical impact for most users. 

The results highlight the progress made by foldable phones in mobile connectivity. At the same time, thermal management and manufacturing costs remain important considerations as manufacturers continue developing thinner and more powerful designs. 

Despite this progress, foldables remain a small part of the overall smartphone market. According to the data cited in the report, devices with flexible displays accounted for 1.4% of smartphones in use worldwide. Counterpoint expects foldable smartphone sales to increase by 20% in 2026, although the category would still represent only around 2% of the global smartphone market. 

With Apple’s iPhone Duo entering the segment, competition is expected to increase, while Samsung currently maintains a strong presence in the foldable market. 

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