What causes low FPS in Pygame?

Surfaces are not converted to the display format so every blit does a slow pixel conversion, or you are redrawing and reloading too much each frame.

How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix Low FPS in Pygame

Quick answer: Call convert or convert_alpha on every loaded image once at load time, reuse surfaces instead of reloading, and limit redraws with dirty rectangles where possible.

Slow Pygame games are almost always blitting unconverted surfaces, which forces a format conversion every frame. Converting once at load is the single biggest win. Here is how.

How to fix it

1. Convert every surface once

After loading an image, call convert (or convert_alpha for transparency) once. This matches the display format so blits are fast memory copies instead of per-pixel conversions every frame.

2. Stop reloading and recreating surfaces

Load images and create fonts and surfaces once, outside the loop. Reloading from disk or re-rendering text every frame is a common, avoidable cost.

3. Limit redraws

Use display.update with a list of dirty rectangles instead of flipping the whole screen when only parts change, and avoid drawing off-screen objects. Cap the frame rate with a Clock to free CPU.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every Pygame error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.

Ship the fix, watch the signature disappear from the next build. That's how you know it's really gone.