8000 Hz: A Closer Look

In general terms, polling rate can be described as the rate at which the data generated by the mouse is transmitted from the mouse to the PC via USB. Polling rate is measured in Hz; i.e., number of times per second. The higher the polling rate—the lower the polling interval—the more frequently the cursor position and any other input events (button inputs) are updated, resulting in improved positional accuracy and generally reduced latency. At 1000 Hz, the polling interval is 1 ms, which means the PC receives a new update every 1 ms. At 2000 Hz, the interval is 0.5 ms, at 4000 Hz, the interval is 0.250 ms, and at 8000 Hz, the interval is 0.125 ms.

8000 Hz: The Technology and How to Use It

In the past, multiple mice claimed to be capable of 2000 or even 3000 Hz polling have been released. However, each and every time, these claims turned out to be inaccurate. All of these mice had one thing in common: They were full-speed devices typically incapable of running at polling rates higher than 1000 Hz without modified USB drivers. The Chakram X, on the other hand, is a high-speed device and thus natively capable of polling rates higher than 1000 Hz. Furthermore, it is equipped with a sensor capable of running at a sufficiently high framerate, which ensures it is not just identical data being sent more frequently.

The Chakram X can be set to 250, 500, 1000, 2000, 4000, or 8000 Hz. However, it is important to note that those values merely denote the maximum applicable polling rate. If the mouse isn't physically moved enough to generate a sufficient number of motion events (for 8000 Hz at least 8000 pixels worth of motion per second), fewer updates will be transmitted, resulting in a lower effective polling rate. Accordingly, using a sufficiently high CPI step on the Chakram X is highly recommended. I would advise using at least 1600 CPI, and possibly even higher steps depending on one's effective in-game sensitivity (turn circumference). The higher the turn circumference, the more physical motion is typically generated, and lower CPI is thus required to saturate the polling rate. Conversely, the lower the turn circumference, the less physical motion is generated, and higher CPI is thus required to saturate the polling rate. Since there is little to no smoothing added at higher CPI steps on the Chakram X, virtually any CPI level can be used without a motion delay penalty. Note that irrespective of the set polling rate, click events are always polled at the applicable maximum.

In order to get the full benefit out of 8000 Hz polling, certain conditions need to be met. First, it is recommended to have a sufficiently powerful CPU; i.e., one with six physical cores and appropriately high IPC to match. Second, the OS has to be capable of 125 μs or lower interrupt moderation. This is true of Windows 8 or higher, where interrupt moderation on XHCI will typically be 50 μs, but not of Windows 7 and lower, where interrupt moderation is never below 1 ms unless changed manually, which isn't trivial to do. On EHCI, interrupt moderation can be expected to be 125 μs on Windows 8 or higher, which is sufficient but not optimal. Third, it is therefore recommended to plug the Chakram X into a USB 3.x port in XHCI mode. Any USB 3.x ports forced into EHCI will be equivalent to a native USB 2.x port. As a general rule of thumb, one should use a USB port native to the CPU and not connect any other high-polling devices to a port of the same hub. Even if all of these conditions are met, actual polling stability during higher workloads will further depend on general system and OS health. As such, it is recommended to use a reasonably optimized OS installation light on bloat in conjunction with the Chakram X.

Performance Testing

In this section, I'll be testing general tracking and polling stability at 2000, 4000, and 8000 Hz each. Motion delay testing has been omitted as I haven't been able to get sufficiently consistent results. For the record, the Chakram X is consistently ahead of the G403.

2000 Hz:

Owing to hardware MotionSync, count distribution is very tight. The Chakram X averages exactly 0.5 ms.

4000 Hz:

Count distribution is marginally worse. The Chakram X averages exactly 0.250 ms.

8000 Hz:

Count distribution yet again is marginally worse. The Chakram X averages exactly 0.125 ms.

Subjective Evaluation

Of course, the performance metrics obtained through empirical testing are just one side of the coin. The more pressing question is whether 8000 Hz is at all noticeable in games, and if so, to which degree.

To properly answer this question, note that someone being unable to notice something does not mean it isn't there objectively, or does not provide an objective advantage. The latter is most definitely true of 8000 Hz polling on the Chakram X, so the matter shifts towards whether said advantage is meaningful and thus noticeable one way or another. That said, playing on a 165 Hz monitor at typically 200 FPS or more, I indeed struggled to notice a difference in terms of latency. As explained above, saturating the full 8000 Hz polling rate takes quite a bit of mouse movement and thus isn't typically reached all the time anyway, so most of the time, the benefit in terms of latency compared to 1000 Hz is around 0.5 ms, which is well below the sensory capabilities of the average human. The greatest effect of 8000 Hz may indeed not be observed in terms of absolute latency, but rather general positional accuracy and smoother cursor feel, more specifically in games requiring high precision in regards to click timing. Particularly games supporting sub-frame input will benefit to a greater degree from 8000 Hz, such as Overwatch or Diabotical with their respective settings enabled. Generally, in order to get any use out of 8000 Hz, I'd recommend using a strong CPU and a 240 Hz or even 360 Hz display. Slower panels will inevitably struggle to even display the granularity afforded by 8000 Hz polling. Those with weaker CPUs may experience worse input response simply due to the higher CPU cost, which means any advantage gained by 8000 Hz immediately cancels itself out.

When choosing between 2000, 4000, and 8000 Hz, I would advise using 4000 Hz. On the Chakram X, click events are always polled at the maximum applicable rate in wired operation, which is why opting for a polling rate below 8000 Hz carries no latency penalty. Hence, the only difference is a minor advantage in terms of motion delay, but since 8000 Hz rarely is fully saturated anyway, the difference in practice is miniscule.

Appendix: List of Tested Games

As there is little reason to use the ASUS ROG Chakram X at polling rates higher than 1000 Hz in non-competitive games, I'll exclusively list games that are typically considered competitive. Please note that a game running fine for me won't necessarily run fine for everyone as it merely means it generally works well with 8000 Hz polling. Conversely, a game not working well at 8000 Hz on a specific system isn't generally incompatible with 8000 Hz polling. Unfortunately, Armoury Crate doesn't support application-specific profiles, so one would have to manually lower the polling rate in games that don't work well with polling rates higher than 1000 Hz.

• Call of Duty: Black Ops II Up to 8000 Hz
• Diabotical Up to 8000 Hz
• KovaaK's Up to 8000 Hz
• Quake Champions Up to 8000 Hz
• Quake Live Up to 8000 Hz