# Measure gaming performance before you tweak: frame time, 1% low, latency

> A repeatable method for Windows 11 26H2 gaming measurements, including passthrough-VM caveats and a ledger for every change.

**Tested on**

- Build: 26300.9711
- Edition: Pro
- Architecture: x64
- Evidence: E1
- Verified: 2026-10-27

## The short answer

Average FPS hides the problem. If a game “feels” bad while the counter says 120, look at **frame time** and **1% low**, then change one variable at a time. A tweak without a before/after measurement is a guess.

> **Caution: Lab status**
>
> This page defines the method. The Tweak Ledger below is a schema example; rows are filled only after a measured run on the lab machine. A passthrough VM is labelled `M-V` and is never presented as a bare-metal result.

## What to capture

| Metric | Why it matters | Tool |
|---|---|---|
| Average FPS | Throughput, easy to over-read | CapFrameX / PresentMon |
| 1% low FPS | The stutter you actually feel | CapFrameX |
| P99 frame time | Worst frames, not the average | CapFrameX |
| DPC/ISR latency | Driver-level stalls | LatencyMon |
| Clocks, temps, power | Confirms the run was comparable | HWiNFO |

## Procedure

- [ ] **Freeze the variables** (Settings)

  Write down the Windows build (`winver`), GPU driver version, game version, resolution, refresh rate, VRR state, power plan and room temperature. A result without these is not comparable.

  Expected: Same build, driver, game version, resolution, quality preset and power plan before and after.

- [ ] **Capture a baseline** (Terminal (admin))

  Use a repeatable scene (built-in benchmark or a saved route). Discard the first cold run. Keep the raw CSV; the page shows the summary, not a screenshot of a number.

  Expected: Five runs of the same 60-second scene; median and 1% low recorded.

- [ ] **Change one thing** (Settings)

  Snapshot the VM or create a restore point first. If two things change, you cannot attribute the result.

  Expected: Exactly one registry, service, driver or in-game setting differs.

- [ ] **Re-capture and compare** (Terminal (admin))

  Run the same five-pass sequence. If the delta is inside the noise band, publish it as “no measurable effect” rather than a win.

  Expected: A delta larger than run-to-run noise, with the same scene and settings.

## Tweak ledger (schema example)

## Passthrough-VM caveats

- **Label it.** A GPU-passthrough VM is `M-V`. Absolute FPS is not a bare-metal number; use it for same-environment comparisons.
- **Anti-cheat can refuse.** Some titles detect virtual machines. Keep a list; test blocked titles on bare metal or do not publish a result.
- **Synthetic vs real:** a built-in benchmark is repeatable but may not represent a real match. Say which one you used.
- **No silent edits:** if you change the VM CPU model, hugepages or pinning between runs, the comparison is invalid.

## What not to claim

- “+30% FPS” from a single run.
- A registry tweak that “reduces input lag” without a latency measurement.
- A VM result presented as if it were a physical PC.
- A tweak that permanently disables Defender, updates or a security boundary.

- [Memory integrity (HVCI): measured cost](https://winbook.fyi/en/windows/gaming/memory-integrity/) — check the security/performance trade-off before disabling it.

## Sources

- [Microsoft — Windows 11 26H2 known issues](https://learn.microsoft.com/en-us/windows/release-health/status-windows-11-26h2)
- [Microsoft — GPU passthrough and anti-cheat (Q&A)](https://learn.microsoft.com/en-us/answers/questions/1530705/hyper-v-data-security-kernel-access-programs)

---

Source: https://winbook.fyi/en/windows/gaming/measure/