Periodic, non-fatal GPU work-submission stall (~7-9s cycle) across multiple renderers on RTX 5080 — distinct from Xid 109/crash reports

Summary:
Reproducible, perfectly periodic stall where the GPU alternates between ~97-98% and ~17-25% utilization on a strict ~7-9 second cycle, across multiple unrelated game engines, with no Xid error, no crash, no driver recovery — this appears distinct from the Xid 109 CTX SWITCH TIMEOUT crash reports (#1080, #1097, ValveSoftware/csgo-osx-linux#3290) and the general desktop stutter in #777.

System:

• Bazzite (Fedora Kinoite-based), KDE Plasma 6, Wayland
• CPU: Intel Core Ultra 7 265K
• GPU: RTX 5080 (GB203), 16GB VRAM
• Driver: nvidia-open, tested 610.43.02 and 595.71.05 (both from the experimental-bleeding-edge branch per in-game diagnostics — no mature/stable branch currently exists for this GPU)
• Display: 5120x2160, tested at 120Hz+VRR and fixed 60Hz/no-VRR — no effect on the pattern

Reproduction matrix (all at max settings, 5120x2160):

Proton is therefore not a required factor (CS2 reproduces natively) — the discriminator looks more like renderer complexity (multi-queue/async-compute usage), present in the three affected titles and absent in TF2's simpler forward renderer.

Key measurement: during the low-utilization phase, GPU clocks/power state do NOT drop (stays P0, ~2780-2820MHz, no HW/SW slowdown flag) — the GPU has full clock/power headroom throughout, it simply isn't being handed work. This also reproduces identically in a completely static scene (game's own pause menu / title screen with no simulation running), ruling out scene-content-driven load variance.

Ruled out: VRAM (never saturated), system RAM/swap, disk I/O (PSI = 0), HDR, native-Wayland vs Xwayland, CPU P-core/E-core pinning (all threads pinned to P-cores via taskset — no change), network/telemetry latency, other GPU clients (nvidia-smi pmon confirms only the game process has load), VRR/refresh-rate/fps-cap combinations, Proton version (Hotfix vs 10.0 — the latter caused an unrelated single Xid 109 hang on savegame load, not the periodic pattern), driver version (610.43.02 vs 595.71.05, same branch).

Happy to provide nvidia-bug-report.sh output, raw nvidia-smi CSV logs, or test further permutations if useful.

Begin with the reproduction matrix and compare the affected DX12/Vulkan titles against Team Fortress 2's clean result. Collect the offered nvidia-bug-report.sh output and raw nvidia-smi CSV logs while observing the reported 7–9 second cycle. Done means identifying a reproducible driver-side cause or narrowing the failure to a specific renderer or submission path.