Quick answer
What this guide helps you determine
A practical explanation of 2KRO, 6KRO and NKRO, including why the advertised value may depend on connection mode.
Begin with the observable browser result, repeat it under the same conditions, and change one connection, setting or application at a time. A browser result narrows likely causes but does not certify hardware or decide a repair.
Scope of this check
N-key rollover (NKRO) means that each pressed key can be reported independently in the supported operating mode. Labels such as 2KRO or 6KRO describe a capability boundary, but the practical result can vary by key pattern, USB or wireless mode, firmware setting and operating-system handling.
Step-by-step method
- Test normal single keys first so a damaged switch is not mistaken for a rollover limit. Then hold a realistic base group—such as W, A and Shift—and add one key at a time while watching the current pressed list.
- Record both the maximum count and the exact first combination that loses a key. A board that reports eight convenient keys may still block a different three-key pattern, so the pattern is more useful than a headline number.
- If the keyboard advertises a selectable NKRO mode, follow its manual and reconnect after changing it. Compare wired, receiver and Bluetooth modes separately because their report formats and power constraints can differ.
What to check first
Use these checkpoints to keep the comparison focused. Record the visible behavior rather than assigning a fault label too early.
- Count registered simultaneous keys
- Test the combinations you actually use
- Compare USB and wireless modes when available
How to read what you see
| Observation | What it can suggest | Useful next check |
|---|---|---|
| Every tested real-world combination remains present | The keyboard handled those combinations in this mode. | Keep the exact combinations as your practical result, not a universal certification. |
| The seventh key consistently disappears | A six-key boot-protocol limit or firmware mode may be active. | Check the manual for 6KRO/NKRO switching and connection limitations. |
| A three-key pattern fails despite higher counts elsewhere | The matrix has a combination-specific blocking boundary. | Rebind one control or choose a keyboard designed for that pattern. |
Common mistakes to avoid
- Do not press keys with an object or body weight.
- Do not include keys intercepted by the operating system in the count.
- Do not assume Bluetooth and wired results must match.
Build evidence another person can use
Write down the exact action, visible result and whether it repeats. Include the browser family, operating-system family, connection type and the single comparison that changed the result. Quote the observation directly—for example, “Every tested real-world combination remains present”—then add where it occurred and which comparison changed it.
Change one condition per comparison and return settings that have no effect. Follow model-specific manufacturer instructions before firmware changes, cleaning, disassembly or warranty action.
When to seek qualified support
If the same problem remains in multiple applications and on another compatible connection or computer, collect the repeatable observations and contact the manufacturer or a qualified technician. Stop using equipment that is physically damaged, unusually hot, wet, sparking or unsafe. Device Test Bench cannot inspect electrical condition or make a repair decision.
Privacy during testing
Our public tests process key events, pointer values, media streams and controller input locally. Do not send private recordings, complete typed text or device identifiers when asking for help. A short description of the behavior, browser and page URL is normally enough.
Questions readers ask
Do most people need full NKRO?
Usually not. What matters is reliable reporting of the combinations used for typing, shortcuts or games.
Why can a keyboard advertise NKRO but show six keys?
The board may be in a compatibility mode, the connection may use a different report format, or the advertised feature may require a firmware toggle.
Primary technical references
The following specifications define the browser APIs discussed in this guide. They are primary web-platform references, not product repair manuals.