What is CapFrameX?

CapFrameX is a Windows benchmarking tool for recording and analyzing game performance. It captures FPS, frametimes, and sensor data while you play, then lets you analyze, plot, and share the results. It is built on Intel's PresentMon for capture and uses RivaTuner Statistics Server (RTSS) for its overlay. If you need detailed, reproducible performance data rather than a single average FPS number, this is the kind of tool you are looking for.

What it captures

While a game is running, CapFrameX records:

• FPS — frames per second over time
• Frametimes — the time each individual frame takes to render
• Sensor data — hardware telemetry captured alongside the run

The tool is described as a source for "detailed and reliable benchmarks," which is the core distinction from simple FPS counters: it keeps the raw per-frame data so you can analyze it after the fact.

How it works under the hood

Two components do the heavy lifting:

Because capture is based on PresentMon, the data reflects what the presentation pipeline actually delivers, not an estimate. The overlay is provided separately by RTSS, so RTSS needs to be present for the overlay to function.

Why frametimes matter more than average FPS

CapFrameX's own blog posts address a common confusion: why analysis can show FPS values lower than what you see in-game. The explanation is that average FPS hides frame-to-frame variation. Two runs can share the same average FPS while one feels smooth and the other stutters. CapFrameX therefore reports metrics such as:

• Frametimes — the per-frame timing that reveals stutter
• Median — the middle value, less skewed by outliers than the mean
• Percentiles — the distribution of performance across the run
• x%-low — the average of the worst x% of frames, a common measure of worst-case smoothness

The site explicitly documents how CapFrameX calculates FPS, so the numbers are traceable rather than opaque.

What you can do with the results

• Analyze a captured run using the built-in metrics
• Plot the data to visualize frametime spikes and trends
• Share results with others through the tool's cloud service

That last point matters for comparisons: instead of trading screenshots, you can share the underlying capture.

Who it is for

CapFrameX suits users who need reliable, detailed benchmarking data — for example, comparing two GPUs, testing a driver update, tuning in-game settings, or verifying that a system maintains consistent frametimes under load. If you only want a quick FPS readout, a simpler overlay is enough; if you need to prove or diagnose performance behavior, the per-frame data here is the point.

To get started, download it from capframex.com and run a capture while playing your game.