"Editor play mode is hard-capped at 60 fps: cvars won't lift it"

You're profiling in the editor's embedded play mode and fps reads exactly 60.0: never higher, never lower (until the scene actually gets heavy). Setting r_frame_sync_enable 0 and fps_max 0 changes nothing. Your GPU profiling shows headroom, but the number won't move.

The editor window is a desktop compositor surface. Its present call is vsync-locked to the monitor's refresh rate (typically 60 Hz). This cap is applied by the OS compositor, not by the engine's own frame-sync cvar. r_frame_sync_enable and fps_max both accept the value (you can read them back as 0), but the compositor's vsync on the editor window's present overrides them.

Don't trust editor play-mode fps as a GPU ceiling measurement. An avg = 60.0 only means "the engine met every 60 Hz deadline": it tells you nothing about actual headroom.

To measure real GPU performance:

1. Launch a standalone build (not embedded play mode) where the engine controls its own swap chain.
2. Use fps_max 0 + r_frame_sync_enable 0 in the standalone window: they work there.
3. Look at the 1% low (p1), not just the average. The real performance knee is where avg < 60 AND the p1 collapses.

For editor-based profiling, track frame time (1000 / fps) trends rather than raw fps: a jump from 16.6 ms to 18 ms is meaningful even when both read as "60 fps" due to the cap.

Under the cap, even the median lies: read the tail

Confirmed on engine 26.07.22: with the compositor cap in force, per-frame dt's median (p50) pins to exactly 16.67 ms in every measurement leg regardless of load, not just the average. The only readable signal is the tail: p99, the single worst frame, and the count of frames over budget, read together with per-system deltas against a quiet (idle/low-load) baseline captured in the same run. A leg that reports "p50 16.67 ms, looks fine" while its p99, worst-frame, and over-budget count climb is a regression; comparing means or medians across legs under vsync hides it completely.

Standalone builds create their own OS window and swap chain, giving the engine full control over present timing. The compositor vsync only affects windows it composites: the editor's embedded viewport is one; a standalone game window with exclusive swap-chain control is not.