Yep, the thread I created -- linkified for other readers.
Even sub-millisecond latency improvements can still add up for elite esports atheletes -- shaving off all those 0.5ms-increasers at all stages of the latency chain, improved mouse, improved display, improved refresh rates, etc.
However, just wanted to generalize, that statistically for the majority of average population, the higher poll rates benefits is far more noticeable fluidity-side rather than latency-side. So I nuanced it with "most" -- still acknowledging the latency benefits that can contribute.
But having both is a bonus -- having cake and eating it too!
A testing caveat though: One big part of the lag decrease of the Viper mouse is the reduced latency of the optical mouse switches. I can actually feel that my Razer 8Khz Viper's optically-actuated mouse buttons "feel faster" -- they are noticeably faster-behaving than the mechanical-contact mouse buttons of most other gaming mice. It's the most tactile-trustfully-clicky mouse I've ever used; that's the optically actuated switches! The design of which also eliminate a lot of need for antibounce latencies. The improvements in clickfeel even still occur when I intentionally reduce poll rate to 1000 Hz or 2000 Hz on the Razer 8Khz Viper. This is partially why for a more apples-vs-apples lagfeel comparison, you have to compare 1000Hz-vs-8000Hz on the same mouse (the Razer 8KHz Viper) to isolate pollrate-related lagfeel improvements, since most of the button lag improvement of the Viper mouse is the faster human actuation of the optical mouse buttons.
Thanks to the optical mouse button switches, it almost feels like the mouse is clicking ahead of itself when I click quickly on the Razer Viper 8KHz -- when I go back to any mechanical-actuated-button mice, I can actually tell the clickfeel difference. I'm not even an esports player though I'm an important person in the advocacy of the technology used by esports athletes. Yet, I can feel the click latency difference even when just using a mere web browser when clicking things in a hurry. There's enough milliseconds of lag savings clearly for me to notice the clickfeel improvements in plain regular Windows use, slight as it may be. Versus other Razer 1000 Hz mice, Logitech 1000 Hz mice, and ASUS 1000 Hz mice (all mechanical-actuated-button).
Combined latency decrease from increased pollrate AND the optical switch AND other optimizations that Razer may have done (e.g. less need for antibounce lag), definitely seem to build up human-noticeably in mere Windows use for me. Somehow my button feels like they're perfectly predicting slightly ahead of my actual clicks. Never had mouse buttons feel this responsive when clicking on local UI's like pulldown menus, buttons, and other Windows GUI elements. Measuring this reliably is another question.
Past tests with mouse lag involved attaching a LED to the mouse button, but that doesn't measure latency before actuation (e.g. click actuation of the switch), so doing the same LED test won't reveal the optical switch speedup, since actuation/pressure/click lag is before LED illumination.
A new test from the first touch to first-actuation would be needed to measure the latency decreases. But I would not be surprised to see a decrease of a few milliseconds with a different lag test from "zero finger pressure" to "mouse event triggered".
I am not surprised that diakou has noticed the benefits...