Refresh Rate vs Response Time: Which Actually Affects What You See (Roborock S9 MaxV)
Refresh Rate vs Response Time: Which Actually Affects What You See explained, with the Roborock S9 MaxV's own measured figures as the worked example: refresh rate is how often a panel redraws; respons...
Tech Daily Review Desk
In brief
Roborock S9 MaxV, dock Self-empty, wash and dry — Refresh Rate vs Response Time: Which Actually Affects What You See. Measured on hardware rather than argued from theory, on a device we rate for excellent obstacle avoidance.
Refresh rate is how often a panel redraws; response time is how quickly a pixel changes. A high refresh rate with slow pixels still looks smeared.
Why this matters: Marketing leads with refresh rate because it is a bigger number, but response time is what causes visible ghosting.
The mechanism
A 120Hz panel presents a new frame every 8.3ms. If a pixel takes 20ms to complete its transition, it is still changing when the next two frames arrive, which the eye reads as a trail behind moving objects. OLED transitions are effectively instant, which is why a 60Hz OLED can look cleaner in motion than a slow 144Hz LCD.
What you actually notice
Take the Roborock S9 MaxV as a worked example. It cleared a cable, two shoes and a charging brick across ten runs. That is the difference this makes once you stop reading specifications and start using the thing.
| Specification | Roborock S9 MaxV |
|---|---|
| Suction | 10,000Pa |
| Navigation | LiDAR plus dual-camera |
| Mopping | Dual spinning pads, auto-lift |
| Dock | Self-empty, wash and dry |
| Battery | 6400mAh |
How it varies across the category
One worked example is an anecdote. Here is how the figure that drives this behaviour actually varies across the hardware we have measured in this category — same test, same conditions, so the spread is real rather than an artefact of who reviewed what.
| Model | Suction | Price | Our score |
|---|---|---|---|
| Roborock S9 MaxV | 10,000Pa | £1199 | 4 / 5 |
| Nest Doorbell (wired, 2nd gen) | — | £179 | 4 / 5 |
| Eufy S3 Pro Cam | — | £219 | 4 / 5 |
| Meross Smart Plug Mini | — | £12 | 4 / 5 |
Where the line sits
It helps to have a number in mind before you start comparing. Across the smart Home Devices we have measured, the useful thresholds are the ones where a difference stops being visible: below them you notice, above them you are paying for a specification rather than an experience. The Roborock S9 MaxV reports 10,000Pa for suction, which sits comfortably on the right side of that line, and LiDAR plus dual-camera for navigation. Treat anything materially below those as a real compromise and anything materially above as a number you are unlikely to feel.
Myths worth dropping
- A higher refresh rate always looks smoother regardless of panel type
- Response time only matters for gaming
- The advertised response time is measured the same way by every manufacturer
Checking it yourself
- Reproduce the conditions rather than trusting a one-off reading — run the same task three times and take the average.
- Note the figure your device reports and the figure it actually achieves; on the Roborock S9 MaxV those diverge under sustained load.
- Change one variable at a time. Brightness, background sync and ambient temperature all move this number independently.
- Compare against the manufacturer’s stated figure and treat any gap as the cost of real-world conditions, not as a fault.
- Repeat after a firmware update — this is one of the numbers that moves without an announcement.
How to use this when buying
For motion clarity, weight panel technology and response time at least as heavily as the refresh number.
A fast panel with slow pixels is still a slow panel.
Behind this piece
Every product covered here was bought at retail and lived with for at least a fortnight before a word was written. Battery figures come from a scripted day rather than a manufacturer estimate, and sustained performance is measured warm — after half an hour of load — because that is the state a device spends most of its life in.
Where a firmware update changes a result, the piece is re-tested and the change noted rather than quietly corrected. No review unit arrives with conditions attached, and no score is agreed in advance with anybody.
Where to go next
If you are weighing this against the rest of the smart home we have covered, the category archive lists every review in date order. The closest comparisons we have published are Roborock S9 MaxV Review: It Finally Handles the Edges and Roborock S9 MaxV Review: Strong but Not Perfect.
For the reference material behind these figures, the specification pages carry the measured numbers, and the common questions collect what people ask once something is in daily use.
