Should motion sync be on or off?
Motion sync adds about half a polling interval of delay: a little over 0.5 ms at 1000 Hz, 0.2 ms at 4000 Hz, and 0.1 ms or nothing at 8000 Hz. Eight mice measured by TechPowerUp, one table, and the setting that follows from it.
Off at 1000 Hz if you care about the last half millisecond, and it barely matters either way at 4000 Hz and above. Motion sync adds roughly half a polling interval of motion delay: around 0.5 ms or a little more at 1000 Hz, 0.2 ms at 4000 Hz, and between nothing and 0.1 ms at 8000 Hz. That pattern holds across eight mice that TechPowerUp measured with the setting on and off.
Measured delay added by motion sync, per mouse
TechPowerUp measures motion delay against a Logitech G403 control using xSum plots. At 1000 Hz the review states the added delay directly, quoted below. At 2000 Hz and above it gives the mouse's lead over the G403 with motion sync off and on, and the added delay is our subtraction of the two.
| Mouse | 1000 Hz wired | 1000 Hz wireless | 2000 Hz | 4000 Hz | 8000 Hz |
|---|---|---|---|---|---|
| LAMZU Maya X | around 0.5 ms | a little more than 0.5 ms | 0.3 | - | 0.1 |
| LAMZU Maya | a bit more than 0.5 ms | roughly 0.5 ms | 0.4 | 0.2 | 0 |
| Teevolution Terra Pro | a bit more than 0.5 ms | a bit more than 0.5 ms | 0.4 | 0.2 | 0.1 |
| SCYROX V8 | a bit more than 0.5 ms | a bit more than 0.5 ms | 0.4 | 0.2 | 0 |
| SCYROX V6 | a bit more than 0.5 ms | a bit more than 0.5 ms | 0.4 | 0.2 | 0 |
| Incott GHERO Pro | a bit more than 0.5 ms | a bit more than 0.5 ms | 0.3 | 0.1 | 0 |
| MCHOSE L7 Pro | close to 0.8 ms | around 0.5 ms | 0.4 | 0.2 | 0.1 |
| Hitscan Hyperlight | close to 1 ms | close to 1 ms | 0.4 | 0.2 | 0 |
A zero means TechPowerUp found that enabling motion sync at that rate had no effect. The dash for the Maya X at 4000 Hz is there because high variance, in the reviewer's words, "prevents determining motion delay reliably". The 2000 to 8000 Hz figures are wireless, except for the L7 Pro, which was also tested wired at those rates and gave the same differences both ways.
The rule: about half a polling interval
Put the medians next to half of each report interval and the pattern is plain:
The cost is denominated in polls, not milliseconds, so "0.5 ms" is only true at 1000 Hz. It is the same half-interval arithmetic as the mean report wait on our polling rate page. The measured values sit a little above half an interval at 2000 and 4000 Hz, but TechPowerUp gives each lead as "roughly" to a tenth of a millisecond, so a difference of two such readings cannot separate 0.25 from 0.3. It does rule out anything near a whole millisecond.
Moving from 1000 Hz to 8000 Hz cuts the mean report wait by 0.44 ms. Turning motion sync on at 1000 Hz adds about 0.5 ms. So at 1000 Hz, motion sync costs slightly more than the entire climb to 8000 Hz saves.
0.5 ms or 1 ms?
Two figures circulate. LAMZU's own FAQ says that when motion sync is turned on, "it will increase the delay by 0.5MS". The other figure is 1 ms, which search summaries attribute to Pulsar. Pulsar's product page for the X2 v2 does not say 1 ms. It says motion sync "may cause some motion-delay (less than 1ms) that is not noticeable during in-game play". That is a ceiling, and it gets repeated without the "less than".
The measurements side with LAMZU. Six of the eight mice land at around 0.5 ms or a bit more at 1000 Hz, wired and wireless. The MCHOSE L7 Pro does the same wireless but reached close to 0.8 ms wired, and the Hitscan Hyperlight measured close to 1 ms both ways. So 1 ms is a real result on one mouse, not the rule, and neither figure applies above 1000 Hz.
What you get for the delay
TechPowerUp describes motion sync as effectively synchronising "SPI reads with USB polls, resulting in very low SPI timing jitter". SPI is the link between the sensor and the mouse's microcontroller. LAMZU says the trajectory becomes "denser" and "clearer and smoother"; Pulsar, which describes the feature as "built into the sensor", says it makes tracking "very accurate". None of the three puts a number on the benefit and none of the reviews measures an in-game effect, so we claim none. Our sensor guide covers the sensor properties that do still differ.
Where these numbers stop applying
Every figure is relative. TechPowerUp notes there is "no way to accurately measure motion delay absolutely without special equipment", and the G403 gets "a slight head start". The leads are not absolute latencies; only the on and off differences are used here.
Firmware changes results. The Maya X was tested on firmware 0.0.0.14, and TechPowerUp warns that results on earlier versions may differ.
Sensor mode interacts with it. On the Maya X, switching to "Competitive" mode put the mouse 0.5 ms ahead wired and 0.9 ms ahead wireless, and motion sync "effectively nullified" that gain. On the GHERO Pro at 1000 Hz with the 8K dongle, a 0.8 ms lead was "largely nullified" the same way. Pick a low-latency sensor mode and motion sync gives most of it back.
Finally, a high rate needs movement to fill it. TechPowerUp points out that 8000 Hz needs at least 8000 pixels worth of motion per second, and advises 1600 CPI or more. With less movement, fewer updates are sent and the effective polling rate falls below the one you set.
What to set
- 1000 Hz, chasing latency: off. It costs about 0.5 ms, which is more than 1000 to 8000 Hz saves.
- 1000 Hz, prefer consistency: on is a defensible choice. The cost is fixed and small next to the render queue in the click-to-photon chain.
- 4000 Hz: either way. The cost is about 0.2 ms.
- 8000 Hz: irrelevant. Most mice ignore the setting, and the rest add about 0.1 ms. The real cost of 8000 Hz is battery life.
Frequently asked questions
Does motion sync add input delay?
Yes. In TechPowerUp's xSum tests of eight mice, enabling it added about 0.5 ms or a bit more at 1000 Hz, roughly 0.3 to 0.4 ms at 2000 Hz, 0.1 to 0.2 ms at 4000 Hz, and 0.1 ms or nothing at 8000 Hz. The cost shrinks as the polling rate rises, in step with the polling interval.
Is motion sync 0.5 ms or 1 ms?
0.5 ms at 1000 Hz is the right figure for most mice. LAMZU states 0.5 ms, and TechPowerUp measured around or a bit more than 0.5 ms on six of eight mice, wired and wireless. Pulsar's product page says "less than 1ms", which is an upper bound, not a measurement. Only the Hitscan Hyperlight came close to 1 ms.
Should I turn motion sync off at 8000 Hz?
It makes almost no difference. On five of the eight mice, enabling it at 8000 Hz had no measurable effect at all, and on the other three it added about 0.1 ms. Leave it however you like.
What does motion sync actually do?
In TechPowerUp's words, it "effectively synchronizes SPI reads with USB polls, resulting in very low SPI timing jitter". SPI is the link between the sensor and the mouse's microcontroller. The sensor data arrives at a steadier point in each poll, at the price of a little delay.