The July 2026 One UI 8.5 security update caused extreme battery drain on S25 Ultra and S24 Ultra units, with some users reporting losses of up to 43% per hour.

“Galaxy S25 Ultra and Galaxy S24 Ultra owners woke up in July 2026 to find their $1,299.99 flagships losing charge faster than a budget phone — not because the hardware failed, but because of a CPU loop triggered by the update.”

vs Marketing: Samsung claims 'Up to 31 hrs of video playback' and that mDNIe technology 'enhances battery usage time', but a software update caused drain rates of up to 43% per hour, rendering these claims temporarily void for a significant portion of the user base.

The S25 Ultra exhibits stuttering below 20% battery, display flickering causing eye fatigue, and benchmark stability scores of only 48–59% under sustained load — worse than the OnePlus 13.

“The phone experiences frustrating stuttering when the battery level falls below 20%, not 15%, but 20%! While the iPhone tends to maintain performance even at low battery levels, the S25 Ultra does not.”

vs Marketing: Samsung markets the Snapdragon 8 Elite at 'up to 4.47 GHz' and positions the device as 'still the superphone to beat', but independent stress tests show 48% GPU stability and 59% CPU stability, trailing direct competitors.

A subset of S25 Ultra units shipped with a violently shaking and vibrating 50MP ultrawide camera, rendering it unusable for video recording.

“Some Samsung Galaxy S25 Ultra owners have reported that their ultrawide camera is extremely shaky and unusable. Videos captured with the ultrawide lens show severe instability.”

vs Marketing: Samsung markets '50 MP Telephoto 5x Optical Zoom' and versatile multi-lens camera capabilities, but a hardware defect in the ultrawide module on affected units makes one of the advertised camera systems non-functional.

Even outside of the July 2026 update incident, multiple owners report the S25 Ultra failing to last a full day, with some recording only 4–4.5 hours of screen-on time.

“After a few weeks of use, I'm encountering significant problems: the battery performance is disappointing, offering only about 4 to 4.5 hours of screen-on time.”

vs Marketing: Samsung claims 'Up to 31 hrs of video playback', but real-world screen-on time for some users is as low as 4–4.5 hours, and one owner states their older Note 20 Ultra outlasts the S25 Ultra, calling Samsung's battery improvement claims 'misleading.'

Reviewers and owners found camera improvements over the S24 Ultra to be minimal, with some aspects feeling like a downgrade, particularly macro performance and low-light reliability.

“After testing the S25 Ultra, I found the differences to be minimal — certain aspects even felt like a downgrade. With a starting price of $1,400, I expected significant enhancements, but the camera improvements were underwhelming.”

vs Marketing: Samsung markets a '200 MP Wide-angle' and '50 MP Telephoto' system implying a premium, best-in-class camera, but users returning from S24 Ultra report negligible real-world gains and specific regressions in macro and low-light shooting.