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., the number of times per second. The higher the polling rate and consequently lower polling interval—the more frequently the cursor position and any other input events (button presses) updates, resulting in improved positional accuracy and generally reduced latency. At 1000 Hz, the polling interval is 1 ms, meaning the PC receives a new update every 1 ms. At 2000 Hz, the interval is 0.5 ms, at 4000 Hz, the interval is 0.25 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 Lift 2 Symm, on the other hand, is a high-speed device and thus natively capable of polling rates higher than 1000 Hz.
Polling rates of 125, 250, 500, 1000, 2000, 4000, or 8000 Hz can be set in the software. 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, it is strongly recommended to use a sufficiently high CPI step in conjunction with the Lift 2 Symm. 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 thus lower CPI is required to saturate the polling rate. Conversely, the lower the turn circumference, the less physical motion is generated, and thus higher CPI is required to saturate the polling rate. On the Lift 2 Symm, the entire CPI range may be used without any motion delay penalty, as no smoothing is applied at any point.
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 at the least. Second, the OS has to be capable of interrupt moderation of 125 μs or lower. 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 easily done. 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 Lift 2 Symm into a USB 3.x port in XHCI mode. Any USB 3.x ports forced into EHCI will behave similarly to a native USB 2.0 port. As a general rule of thumb, one should be using 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 without bloat in conjunction with the Lift 2 Symm.
In this section, I'll be testing general tracking, polling stability, and motion delay for 2000, 4000, and 8000 Hz. All testing has been performed at 3200 CPI. Please note that the G403 is moved first and thus receives a slight head start.
2000 Hz:
No oddities in regard to tracking, and MotionSync appears to be enabled. The Lift 2 Symm is ahead of the G403 by roughly 0.7 ms. Exactly 0.5 ms are averaged, but bouts of elevated noise are relatively common.
4000 Hz:
No oddities in regard to tracking, and MotionSync appears to be disabled. The Lift 2 Symm is ahead of the G403 by roughly 1.0 ms. Exactly 0.25 ms are averaged, but bouts of elevated noise are relatively common.
8000 Hz:
The odd missed poll is visible, and MotionSync appears to be disabled. The Lift 2 Symm is ahead of the G403 by roughly 1.0 ms. Only 0.140 ms instead of the target interval of 0.125 ms are averaged, which is due to polling momentarily reverting to intervals of 0.250 ms:
Whenever this happens, a third dotted line either shows up or disappears in xCount. In the plot above, for instance, the 0.250 interval period lasts from time index 3000 (ms) to 3400.
Subjective Evaluation
Of course, the performance metrics obtained through empirical testing are just one side of the coin. The more pressing question is whether 4000 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 with the Lift 2 Symm, 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 compared to 1000 Hz. 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 regarding 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, 4000 Hz may be the preferred choice, as MotionSync appears to be disabled, and none of the issues observed at 8000 Hz are present. Click latency is the same regardless of polling rate.
Appendix: List of Tested Games
As there is little reason to use 2000, 4000, or 8000 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 4000 Hz polling. Conversely, a game not working well at 8000 Hz on a specific system isn't generally incompatible with 8000 Hz polling.
- 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