The OnePlus 3 and the OnePlus 3T are among the best Android smartphones you could buy right now (or not, in the case of the OnePlus 3). Mix great hardware with an open software approach (compared to other popular OEMs) and what you get is a flagships that is closest to the Nexus of old in the developer scene of 2016.

In fact, our forums for the OnePlus 3 attract more traffic than our forums for the Nexus 6P, which was the last Nexus flagship. But not everything is rosy with the OnePlus 3/3T. As of late, users have been complaining about an issue that should not exist on a 2016 flagship. Particularly, despite all of its hardware prowess, the OnePlus 3/3T have poor performance with respect to touch latency.

What is touch latency, you ask? This video from Microsoft Research explains and demonstrates touch latency and its issues in a very easy to understand form:

The delay between the response on the touchscreen to your input is what constitutes touch latency. Modern flagship devices, barring the OnePlus 3/3T that is, typically have latency at around 50ms. But a French review at Les Numériques quoted the touch delay on the OnePlus 3T to be at 93 ms, which as the video above would demonstrate, is unacceptable in high interaction scenarios.

Several users and developers have voiced their displeasure at the current state of touch latency on the flagship product. The issue has been brought up several times in the OnePlus forums, our device forums and on Reddit as well, gathering hundreds of votes and comments. XDA Recognized Developer Arter97 commented on the issue at OnePlus's forums, and gave his thoughts on the matter:

OnePlus 3/3T needs touch firmware (in /system/etc/firmware/tp, closed source) tuning for better latency. The latest 3.5.3 update on the 3T is still not good enough (tried it myself).Currently, the "move sensitivity" on the OnePlus 3 is set too big, which results in latency. If you touch the screen and move the finger around very little (like 3~5mm), it won't be registered as a scroll. This is because the "move sensitivity" is set too big. We are on a 5.5" screen. I think it'll be totally fine to reduce the threshold a bit. (If the threshold is set too small, a tap will be registered as a scroll. If it's set too big, a scroll will be registered as a tap and increase latency.)

As Arter97 mentions, the touch latency delay is not to be confused with smoothness. As we tested out in our hardware review of the OnePlus 3 and the OnePlus 3T, both the devices output exemplary real-world performance. You are unlikely to notice these latency issues in quick and sparse reaction scenarios, as the issue becomes much more apparent when you have numerous screen interactions like while typing, or when doing short scrolling interactions. And, you are much more likely to notice the issues if you come from other flagship devices with better touch response timings, like the Pixel XL. The latency troubles do not make the phone unusable, but they do perceptibly affect the device's overall responsiveness.

The OnePlus 3/3T need tweaking on the firmware level to help combat these issues. It is indeed a shame to have the experience of quality hardware marred by issues that should not be so pressing in 2016. It also bears to mention that the OnePlus 3/3T will not be receiving Android 7.1 Nougat right off the bat, so the touch latency improvements that this update brings across Android is unlikely to be seen here as well (unless OnePlus has been listening and cooks a fix). Our best bet right now is to have OnePlus issue fixes and improvements to this end, and hope that Android 7.1 further improves the scenario as well.

What are your thoughts on the OnePlus 3/3T's touch latency issues? Have you noticed input lag before? Let us know in the comments below!