Keyboard event queue size
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Recommendation
Leave as defaultLeave the default value — 100 events.
A smaller queue does not reduce input latency and loses events when it overflows. Increasing it is worth doing only after confirmed overflow errors and driver diagnostics.
- Default value
- 100 events
- FPS and memory
- FPS is not affected
What changes
Section titled “What changes”The keyboard class driver accumulates input events in a queue of a given size: the parameter determines how many keyboard events can wait to be processed before the queue fills up. According to Microsoft documentation, the size is also used when calculating the driver’s internal buffer in non-paged memory. The default and BoosterX-recommended value is 100 events.
The queue is a reserve for peak load, not “extra lag”: reducing the size does not lower input latency. When the queue fills up, events are lost, and overflow warnings appear in the system log. Increasing it helps in two cases (according to BoosterX’s visible description): confirmed buffer overflows and unstable USB power.
Exceptions and differences
Section titled “Exceptions and differences”Why the tweak is under “Legacy”: changing the size is a tool for eliminating confirmed overflows, not an optimization. According to BoosterX tests, lowering it does not affect latency, but merely causes overflow errors and loss of entered characters (according to the visible description). The mechanism is shared by keyboard and mouse — the mouse-specific case is covered in the article “Mouse event queue size”.
How to verify the result
Section titled “How to verify the result”After changing and rebooting, check fast typing, key holding and long key combinations. Look for overflow warnings in the system log of “Event Viewer”. Without a measurable difference, it is safer to return the default value.
How to change and revert
Section titled “How to change and revert”In BoosterX, open “Optimization” → “Legacy” → “KeyboardDataQueueSize” (the item in the application list is named by the key without translation), set the value and click “Apply”. If “Instant apply” is enabled, a separate click is not required. Reboot the PC and check input.
Confirmation
Section titled “Confirmation”- Microsoft: Configuration of Keyboard and Mouse Class Drivers, checked 2026-09-19 — class driver event buffer in non-paged memory.
- Keyboard ports research — verified keyboard class parameters.
Last check: 2026-09-20.