What is measured
Two things your machine can actually know about itself:
- How long drivers hold a processor core. While a driver is inside an interrupt or a deferred call, that core draws nothing and reads no input. It runs above every thread priority, so it appears in no frame-time graph and in no task manager.
- How evenly your input device reports, from the raw input stream, timed with the high-resolution counter rather than the system clock.
The colours
A driver's worst measured hold decides its colour:
| Colour | Worst hold | What it means |
|---|---|---|
| Green | under 1 ms | normal. Nothing to do. |
| Amber | 1 ms and above | enough to cost a mouse report, or most of a frame at 240 Hz |
| Red | 4 ms and above | this is the thing to fix before anything else on this page |
Individual samples are coloured against your own median rather than a fixed number: over twice the median is amber, over four times is red. A machine that is uniformly slow and a machine that is mostly fast with spikes are different problems, and a fixed threshold would hide the difference.
What a good machine looks like
Most drivers under 0.5 ms, worst case under 1 ms, and no single driver standing far above the rest. That is the realistic target, and plenty of otherwise fine machines have one amber entry that never causes a symptom.
An amber line is not a problem you must fix. It is a candidate. If you have no stutter, it explains nothing and there is nothing to chase.
What this number is not
It is a floor, not a total. Not included, because they cannot be measured from this machine:
- the game's own input sampling
- its render queue
- the GPU's work
- the panel's response time
Any tool that prints one "input lag: 14 ms" number is estimating those parts. We show what can be measured and say what is missing, which is less satisfying and more honest.
If a driver is red
The fix is almost always updating that driver — from the hardware maker, not from a driver-updater tool. The page names the file so you can look it up.
Related
Did this page help?
What was missing, or what did not work? We read every one of these.
If this page did not solve it, write to us — say which article you read, and we will fix the article.